Oracle, schemas and transactions

Hi all,
I'd like to know if the Sybase ASE feature of being able to handle in the same transaction (with the same TCP/IP physical connection) different databases hosted on the same machine (dataserver) can be translated in Oracle ?
the schema concept may be related to this concept, isn't it ?
May I find under the same database (oracle instance) the same table with different shcemas (aka owners) that is to say: is the following use case a valid one ?
MyDB
dbo.mytable jerome.mytable
Is the following pseudo code valid in Oracle:
begin trans
INSERT INTO dbo.mytable VALUEs (....)
INSERT INTO jerome.mytable VALUES (...)
COMMIT
Thanks for any pointer or answer
I'm far from being an Oracle guru!!!
Cheers
Jerome

Thanks for your help!!!
I thought (but was wrong) that Oracle didn't support the creation of the same table with different schemas...
I don't have a running Oracle server to test!!!
Thanks
Jerome

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    SELECT customer_no, payments from customer C1
    WHERE 3<=(SELECT COUNT(*) from customer C2
    WHERE C1.payment <= C2.payment)
    32 minvalue.sql Select the Nth lowest value from a table
    select level, min('col_name') from my_table where level = '&n' connect by prior ('col_name') <
    'col_name')
    group by level;
    Example:
    Given a table called emp with the following columns:
    -- id number
    -- name varchar2(20)
    -- sal number
    -- For the second lowest salary:
    -- select level, min(sal) from emp
    -- where level=2
    -- connect by prior sal < sal
    -- group by level
    33 maxvalue.sql Select the Nth Highest value from a table
    select level, max('col_name') from my_table where level = '&n' connect by prior ('col_name') >
    'col_name')
    group by level;
    Example:
    Given a table called emp with the following columns:
    -- id number
    -- name varchar2(20)
    -- sal number
    -- For the second highest salary:
    -- select level, max(sal) from emp
    -- where level=2
    -- connect by prior sal > sal
    -- group by level
    34 How you will avoid your query from using indexes?
    SELECT * FROM emp
    Where emp_no+' '=12345;
    i.e you have to concatenate the column name with space within codes in the where condition.
    SELECT /*+ FULL(a) */ ename, emp_no from emp
    where emp_no=1234;
    i.e using HINTS
    35 How you will avoid duplicating records in a query?
    By using DISTINCT
    36 How you were passing cursor variables in PL/SQL 2.2?
    In PL/SQL 2.2 cursor variables cannot be declared in a package.This is because the storage for a cursor variable has to be allocated using Pro*C or OCI with version 2.2, the only means of passing a cursor variable to a PL/SQL block is via bind variable or a procedure parameter.
    37 How you open and close a cursor variable.Why it is required?
    OPEN cursor variable FOR SELECT...Statement
    CLOSE cursor variable In order to associate a cursor variable with a particular SELECT statement OPEN syntax is used. In order to free the resources used for the query CLOSE statement is used.
    38 How will you delete duplicating rows from a base table?
    delete from table_name where rowid not in (select max(rowid) from table group by duplicate_values_field_name); or
    delete duplicate_values_field_name dv from table_name ta where rowid <(select min(rowid) from table_name tb where ta.dv=tb.dv);
    39 How do you find the numbert of rows in a Table ?
    A bad answer is count them (SELECT COUNT(*) FROM table_name)
    A good answer is :-
    'By generating SQL to ANALYZE TABLE table_name COUNT STATISTICS by querying Oracle System Catalogues (e.g. USER_TABLES or ALL_TABLES).
    The best answer is to refer to the utility which Oracle released which makes it unnecessary to do ANALYZE TABLE for each Table individually.
    40 Find out nth highest salary from emp table
    SELECT DISTINCT (a.sal) FROM EMP A WHERE &N = (SELECT COUNT (DISTINCT (b.sal)) FROM EMP B WHERE a.sal<=b.sal);
    For Eg:-
    Enter value for n: 2
    SAL
    3700
    41 Display the records between two range?
    select rownum, empno, ename from emp where rowid in (select rowid from emp where rownum <=&upto minus select rowid from emp where rownum<&Start);
    42 Display the number value in Words?
    SQL> select sal, (to_char(to_date(sal,'j'), 'jsp'))
    from emp;
    the output like,
    SAL (TO_CHAR(TO_DATE(SAL,'J'),'JSP'))
    800 eight hundred
    1600 one thousand six hundred
    1250 one thousand two hundred fifty
    If you want to add some text like, Rs. Three Thousand only.
    SQL> select sal "Salary ",
    (' Rs. '|| (to_char(to_date(sal,'j'), 'Jsp'))|| ' only.'))
    "Sal in Words" from emp
    Salary Sal in Words
    800 Rs. Eight Hundred only.
    1600 Rs. One Thousand Six Hundred only.
    1250 Rs. One Thousand Two Hundred Fifty only.
    43 Display Odd/ Even number of records
    Odd number of records:
    select * from emp where (rowid,1) in (select rowid, mod(rownum,2) from emp);
    Output:-
    1
    3
    5
    Even number of records:
    select * from emp where (rowid,0) in (select rowid, mod(rownum,2) from emp)
    Output:-
    2
    4
    6
    44 Difference between procedure and function.
    Functions are named PL/SQL blocks that return a value and can be called with arguments procedure a named block that can be called with parameter. A procedure all is a PL/SQL statement by itself, while a Function call is called as part of an expression.
    45 Difference between NO DATA FOUND and %NOTFOUND
    NO DATA FOUND is an exception raised only for the SELECT....INTO statements when the where clause of the querydoes not match any rows. When the where clause of the explicit cursor does not match any rows the %NOTFOUND attribute is set to TRUE instead.
    46 Difference between database triggers and form triggers?
    Data base trigger(DBT) fires when a DML operation is performed on a data base table. Form trigger(FT) Fires when user presses a key or navigates between fields on the screen
    Can be row level or statement level No distinction between row level and statement level.
    Can manipulate data stored in Oracle tables via SQL Can manipulate data in Oracle tables as well as variables in forms.
    Can be fired from any session executing the triggering DML statements. Can be fired only from the form that define the trigger.
    Can cause other database triggers to fire.Can cause other database triggers to fire, but not other form triggers.
    47 Difference between an implicit & an explicit cursor.
    PL/SQL declares a cursor implicitly for all SQL data manipulation statements, including quries that return only one row. However,queries that return more than one row you must declare an explicit cursor or use a cursor FOR loop.
    Explicit cursor is a cursor in which the cursor name is explicitly assigned to a SELECT statement via the CURSOR...IS statement. An implicit cursor is used for all SQL statements Declare, Open, Fetch, Close. An explicit cursors are used to process multirow SELECT statements An implicit cursor is used to process INSERT, UPDATE, DELETE and single row SELECT. .INTO statements.
    48 Can you use a commit statement within a database trigger?
    No.
    49 Can the default values be assigned to actual parameters?
    Yes
    50 Can cursor variables be stored in PL/SQL tables.If yes how. If not why?
    No, a cursor variable points a row which cannot be stored in a two-dimensional PL/SQL table.
    51 Can a primary key contain more than one columns?
    Yes
    52 Can a function take OUT parameters. If not why?
    No. A function has to return a value,an OUT parameter cannot return a value.
    53 What are various joins used while writing SUBQUERIES?
    Self join-Its a join foreign key of a table references the same table. Outer Join--Its a join condition used where One can query all the rows of one of the tables in the join condition even though they don't satisfy the join condition.
    Equi-join--Its a join condition that retrieves rows from one or more tables in which one or more columns in one table are equal to one or more columns in the second table.
    54 Differentiate between TRUNCATE and DELETE
    TRUNCATE deletes much faster than DELETE
    TRUNCATE
    DELETE
    It is a DDL statement It is a DML statement
    It is a one way trip,cannot ROLLBACK One can Rollback
    Doesn't have selective features (where clause) Has
    Doesn't fire database triggers Does
    It requires disabling of referential constraints. Does not require
    1 What is PL/SQL ?
    PL/SQL is a procedural language that has both interactive SQL and procedural programming language constructs such as iteration, conditional branching.
    2 Write the order of precedence for validation of a column in a table ?
    I. done using Database triggers.
    ii. done using Integarity Constraints.
    I & ii.
    Exception :
    3 Where the Pre_defined_exceptions are stored ?
    In the standard package.
    Procedures, Functions & Packages ;
    4 What are % TYPE and % ROWTYPE ? What are the advantages of using these over datatypes?
    % TYPE provides the data type of a variable or a database column to that variable.
    % ROWTYPE provides the record type that represents a entire row of a table or view or columns selected in the cursor.
    The advantages are : I. Need not know about variable's data type
    ii. If the database definition of a column in a table changes, the data type of a variable changes accordingly.
    5 What will happen after commit statement ?
    Cursor C1 is
    Select empno,
    ename from emp;
    Begin
    open C1; loop
    Fetch C1 into
    eno.ename;
    Exit When
    C1 %notfound;-----
    commit;
    end loop;
    end;
    The cursor having query as SELECT .... FOR UPDATE gets closed after COMMIT/ROLLBACK.
    The cursor having query as SELECT.... does not get closed even after COMMIT/ROLLBACK.
    6 What is the basic structure of PL/SQL ?
    PL/SQL uses block structure as its basic structure. Anonymous blocks or nested blocks can be used in PL/SQL.
    7 What is Raise_application_error ?
    Raise_application_error is a procedure of package DBMS_STANDARD which allows to issue an user_defined error messages from stored sub-program or database trigger.
    8 What is Pragma EXECPTION_INIT ? Explain the usage ?
    The PRAGMA EXECPTION_INIT tells the complier to associate an exception with an oracle error. To get an error message of a specific oracle error.
    e.g. PRAGMA EXCEPTION_INIT (exception name, oracle error number)
    9 What is PL/SQL table ?
    Objects of type TABLE are called "PL/SQL tables", which are modeled as (but not the same as) database tables, PL/SQL tables use a primary PL/SQL tables can have one column and a primary key.
    Cursors
    10 What is Overloading of procedures ?
    The Same procedure name is repeated with parameters of different datatypes and parameters in different positions, varying number of parameters is called overloading of procedures.
    e.g. DBMS_OUTPUT put_line
    What is a package ? What are the advantages of packages ?
    11 What is difference between a PROCEDURE & FUNCTION ?
    A FUNCTION is always returns a value using the return statement.
    A PROCEDURE may return one or more values through parameters or may not return at all.
    12 What is difference between a Cursor declared in a procedure and Cursor declared in a package specification ?
    A cursor declared in a package specification is global and can be accessed by other procedures or procedures in a package.
    A cursor declared in a procedure is local to the procedure that can not be accessed by other procedures.
    13 What is difference between % ROWTYPE and TYPE RECORD ?
    % ROWTYPE is to be used whenever query returns a entire row of a table or view.
    TYPE rec RECORD is to be used whenever query returns columns of different
    table or views and variables.
    E.g. TYPE r_emp is RECORD (eno emp.empno% type,ename emp ename %type
    e_rec emp% ROWTYPE
    cursor c1 is select empno,deptno from emp;
    e_rec c1 %ROWTYPE.
    14 What is an Exception ? What are types of Exception ?
    Exception is the error handling part of PL/SQL block. The types are Predefined and user defined. Some of Predefined exceptions are.
    CURSOR_ALREADY_OPEN
    DUP_VAL_ON_INDEX
    NO_DATA_FOUND
    TOO_MANY_ROWS
    INVALID_CURSOR
    INVALID_NUMBER
    LOGON_DENIED
    NOT_LOGGED_ON
    PROGRAM-ERROR
    STORAGE_ERROR
    TIMEOUT_ON_RESOURCE
    VALUE_ERROR
    ZERO_DIVIDE
    OTHERS.
    15 What is a stored procedure ?
    A stored procedure is a sequence of statements that perform specific function.
    16 What is a database trigger ? Name some usages of database trigger ?
    Database trigger is stored PL/SQL program unit associated with a specific database table. Usages are Audit data modifications, Log events transparently, Enforce complex business rules Derive column values automatically, Implement complex security authorizations. Maintain replicate tables.
    17 What is a cursor for loop ?
    Cursor for loop implicitly declares %ROWTYPE as loop index,opens a cursor, fetches rows of values from active set into fields in the record and closes
    when all the records have been processed.
    eg. FOR emp_rec IN C1 LOOP
    salary_total := salary_total +emp_rec sal;
    END LOOP;
    18 What is a cursor ? Why Cursor is required ?
    Cursor is a named private SQL area from where information can be accessed. Cursors are required to process rows individually for queries returning multiple rows.
    19 What happens if a procedure that updates a column of table X is called in a database trigger of the same table ?
    Mutation of table occurs.
    20 What are two virtual tables available during database trigger execution ?
    The table columns are referred as OLD.column_name and NEW.column_name.
    For triggers related to INSERT only NEW.column_name values only available.
    For triggers related to UPDATE only OLD.column_name NEW.column_name values only available.
    For triggers related to DELETE only OLD.column_name values only available.
    21 What are two parts of package ?
    The two parts of package are PACKAGE SPECIFICATION & PACKAGE BODY.
    Package Specification contains declarations that are global to the packages and local to the schema.
    Package Body contains actual procedures and local declaration of the procedures and cursor declarations.
    22 What are the two parts of a procedure ?
    Procedure Specification and Procedure Body.
    23 What are the return values of functions SQLCODE and SQLERRM ?
    SQLCODE returns the latest code of the error that has occurred.
    SQLERRM returns the relevant error message of the SQLCODE.
    24 What are the PL/SQL Statements used in cursor processing ?
    DECLARE CURSOR cursor name, OPEN cursor name, FETCH cursor name INTO or Record types, CLOSE cursor name.
    25 What are the modes of parameters that can be passed to a procedure ?
    IN,OUT,IN-OUT parameters.
    26 What are the datatypes a available in PL/SQL ?
    Some scalar data types such as NUMBER, VARCHAR2, DATE, CHAR, LONG, BOOLEAN.
    Some composite data types such as RECORD & TABLE.
    27 What are the cursor attributes used in PL/SQL ?
    %ISOPEN - to check whether cursor is open or not
    % ROWCOUNT - number of rows fetched/updated/deleted.
    % FOUND - to check whether cursor has fetched any row. True if rows are fetched.
    % NOT FOUND - to check whether cursor has fetched any row. True if no rows are featched.
    These attributes are proceeded with SQL for Implicit Cursors and with Cursor name for Explicit Cursors.
    28 What are the components of a PL/SQL Block ?
    Declarative part, Executable part and Exception part.
    Datatypes PL/SQL
    29 What are the components of a PL/SQL block ?
    A set of related declarations and procedural statements is called block.
    30 What are advantages fo Stored Procedures /
    Extensibility,Modularity, Reusability, Maintainability and one time compilation.
    1 What is PL/SQL ?
    PL/SQL is a procedural language that has both interactive SQL and procedural programming language constructs such as iteration, conditional branching.
    2 Write the order of precedence for validation of a column in a table ?
    I. done using Database triggers.
    ii. done using Integarity Constraints.
    I & ii.
    Exception :
    3 Where the Pre_defined_exceptions are stored ?
    In the standard package.
    Procedures, Functions & Packages ;
    4 What are % TYPE and % ROWTYPE ? What are the advantages of using these over datatypes?
    % TYPE provides the data type of a variable or a database column to that variable.
    % ROWTYPE provides the record type that represents a entire row of a table or view or columns selected in the cursor.
    The advantages are : I. Need not know about variable's data type
    ii. If the database definition of a column in a table changes, the data type of a variable changes accordingly.
    5 What will happen after commit statement ?
    Cursor C1 is
    Select empno,
    ename from emp;
    Begin
    open C1; loop
    Fetch C1 into
    eno.ename;
    Exit When
    C1 %notfound;-----
    commit;
    end loop;
    end;
    The cursor having query as SELECT .... FOR UPDATE gets closed after COMMIT/ROLLBACK.
    The cursor having query as SELECT.... does not get closed even after COMMIT/ROLLBACK.
    6 What is the basic structure of PL/SQL ?
    PL/SQL uses block structure as its basic structure. Anonymous blocks or nested blocks can be used in PL/SQL.
    7 What is Raise_application_error ?
    Raise_application_error is a procedure of package DBMS_STANDARD which allows to issue an user_defined error messages from stored sub-program or database trigger.
    8 What is Pragma EXECPTION_INIT ? Explain the usage ?
    The PRAGMA EXECPTION_INIT tells the complier to associate an exception with an oracle error. To get an error message of a specific oracle error.
    e.g. PRAGMA EXCEPTION_INIT (exception name, oracle error number)
    9 What is PL/SQL table ?
    Objects of type TABLE are called "PL/SQL tables", which are modeled as (but not the same as) database tables, PL/SQL tables use a primary PL/SQL tables can have one column and a primary key.
    Cursors
    10 What is Overloading of procedures ?
    The Same procedure name is repeated with parameters of different datatypes and parameters in different positions, varying number of parameters is called overloading of procedures.
    e.g. DBMS_OUTPUT put_line
    What is a package ? What are the advantages of packages ?
    11 What is difference between a PROCEDURE & FUNCTION ?
    A FUNCTION is always returns a value using the return statement.
    A PROCEDURE may return one or more values through parameters or may not return at all.
    12 What is difference between a Cursor declared in a procedure and Cursor declared in a package specification ?
    A cursor declared in a package specification is global and can be accessed by other procedures or procedures in a package.
    A cursor declared in a procedure is local to the procedure that can not be accessed by other procedures.
    13 What is difference between % ROWTYPE and TYPE RECORD ?
    % ROWTYPE is to be used whenever query returns a entire row of a table or view.
    TYPE rec RECORD is to be used whenever query returns columns of different
    table or views and variables.
    E.g. TYPE r_emp is RECORD (eno emp.empno% type,ename emp ename %type
    e_rec emp% ROWTYPE
    cursor c1 is select empno,deptno from emp;
    e_rec c1 %ROWTYPE.
    14 What is an Exception ? What are types of Exception ?
    Exception is the error handling part of PL/SQL block. The types are Predefined and user defined. Some of Predefined exceptions are.
    CURSOR_ALREADY_OPEN
    DUP_VAL_ON_INDEX
    NO_DATA_FOUND
    TOO_MANY_ROWS
    INVALID_CURSOR
    INVALID_NUMBER
    LOGON_DENIED
    NOT_LOGGED_ON
    PROGRAM-ERROR
    STORAGE_ERROR
    TIMEOUT_ON_RESOURCE
    VALUE_ERROR
    ZERO_DIVIDE
    OTHERS.
    15 What is a stored procedure ?
    A stored procedure is a sequence of statements that perform specific function.
    16 What is a database trigger ? Name some usages of database trigger ?
    Database trigger is stored PL/SQL program unit associated with a specific database table. Usages are Audit data modifications, Log events transparently, Enforce complex business rules Derive column values automatically, Implement complex security authorizations. Maintain replicate tables.
    17 What is a cursor for loop ?
    Cursor for loop implicitly declares %ROWTYPE as loop index,opens a cursor, fetches rows of values from active set into fields in the record and closes
    when all the records have been processed.
    eg. FOR emp_rec IN C1 LOOP
    salary_total := salary_total +emp_rec sal;
    END LOOP;
    18 What is a cursor ? Why Cursor is required ?
    Cursor is a named private SQL area from where information can be accessed. Cursors are required to process rows individually for queries returning multiple rows.
    19 What happens if a procedure that updates a column of table X is called in a database trigger of the same table ?
    Mutation of table occurs.
    20 What are two virtual tables available during database trigger execution ?
    The table columns are referred as OLD.column_name and NEW.column_name.
    For triggers related to INSERT only NEW.column_name values only available.
    For triggers related to UPDATE only OLD.column_name NEW.column_name values only available.
    For triggers related to DELETE only OLD.column_name values only available.
    21 What are two parts of package ?
    The two parts of package are PACKAGE SPECIFICATION & PACKAGE BODY.
    Package Specification contains declarations that are global to the packages and local to the schema.
    Package Body contains actual procedures and local declaration of the procedures and cursor declarations.
    22 What are the two parts of a procedure ?
    Procedure Specification and Procedure Body.
    23 What are the return values of functions SQLCODE and SQLERRM ?
    SQLCODE returns the latest code of the error that has occurred.
    SQLERRM returns the relevant error message of the SQLCODE.
    24 What are the PL/SQL Statements used in cursor processing ?
    DECLARE CURSOR cursor name, OPEN cursor name, FETCH cursor name INTO or Record types, CLOSE cursor name.
    25 What are the modes of parameters that can be passed to a procedure ?
    IN,OUT,IN-OUT parameters.
    26 What are the datatypes a available in PL/SQL ?
    Some scalar data types such as NUMBER, VARCHAR2, DATE, CHAR, LONG, BOOLEAN.
    Some composite data types such as RECORD & TABLE.
    27 What are the cursor attributes used in PL/SQL ?
    %ISOPEN - to check whether cursor is open or not
    % ROWCOUNT - number of rows fetched/updated/deleted.
    % FOUND - to check whether cursor has fetched any row. True if rows are fetched.
    % NOT FOUND - to check whether cursor has fetched any row. True if no rows are featched.
    These attributes are proceeded with SQL for Implicit Cursors and with Cursor name for Explicit Cursors.
    28 What are the components of a PL/SQL Block ?
    Declarative part, Executable part and Exception part.
    Datatypes PL/SQL
    29 What are the components of a PL/SQL block ?
    A set of related declarations and procedural statements is called block.
    30 What are advantages fo Stored Procedures /
    Extensibility,Modularity, Reusability, Maintainability and one time compilation.
    31 Name the tables where characteristics of Package, procedure and functions are stored ?
    User_objects, User_Source and User_error.
    32 Is it possible to use Transaction control Statements such a ROLLBACK or COMMIT in Database Trigger ? Why ?
    It is not possible. As triggers are defined for each table, if you use COMMIT of ROLLBACK in a trigger, it affects logical transaction processing.
    33 How packaged procedures and functions are called from the following?
    a. Stored procedure or anonymous block
    b. an application program such a PRC C, PRO COBOL
    c. SQL *PLUS
    a. PACKAGE NAME.PROCEDURE NAME (parameters);
    variable := PACKAGE NAME.FUNCTION NAME (arguments);
    EXEC SQL EXECUTE
    b.
    BEGIN
    PACKAGE NAME.PROCEDURE NAME (parameters)
    variable := PACKAGE NAME.FUNCTION NAME (arguments);
    END;
    END EXEC;
    c. EXECUTE PACKAGE NAME.PROCEDURE if the procedures does not have any
    out/in-out parameters. A function can not be called.
    34 How many types of database triggers can be specified on a table ? What are they ?
    Insert Update Delete
    Before Row o.k. o.k. o.k.
    After Row o.k. o.k. o.k.
    Before Statement o.k. o.k. o.k.
    After Statement o.k. o.k. o.k.
    If FOR EACH ROW clause is specified, then the trigger for each Row affected by the statement.
    If WHEN clause is specified, the trigger fires according to the returned Boolean value.
    35 Give the structure of the procedure ?
    PROCEDURE name (parameter list.....)
    is
    local variable declarations
    BEGIN
    Executable statements.
    Exception.
    exception handlers
    end;
    36 Give the structure of the function ?
    FUNCTION name (argument list .....) Return datatype is
    local variable declarations
    Begin
    executable statements
    Exception
    execution handlers
    End;
    37 Explain the usage of WHERE CURRENT OF clause in cursors ?
    WHERE CURRENT OF clause in an UPDATE,DELETE statement refers to the latest row fetched from a cursor.
    Database Triggers
    38 Explain the two type of Cursors ?
    There are two types of cursors, Implicit Cursor and Explicit Cursor.
    PL/SQL uses Implicit Cursors for queries.
    User defined cursors are called Explicit Cursors. They can be declared and used.
    39 Explain how procedures and functions are called in a PL/SQL block ?
    Function is called as part of an expression.
    sal := calculate_sal ('a822');
    procedure is called as a PL/SQL statement
    calculate_bonus ('A822');
    Programmatic Constructs
    Last Update: September 06, 2004
    1 What are the different types of PL/SQL program units that can be defined and stored in ORACLE database ?
    Procedures and Functions,Packages and Database Triggers.
    2 What are the differences between Database Trigger and Integrity constraints ?
    A declarative integrity constraint is a statement about the database that is always true. A constraint applies to existing data in the table and any statement that manipulates the table.
    A trigger does not apply to data loaded before the definition of the trigger, therefore, it does not guarantee all data in a table conforms to the rules established by an associated trigger.
    A trigger can be used to enforce transitional constraints where as a declarative integrity constraint cannot be used.
    3 What is difference between Procedures and Functions ?
    A Function returns a value to the caller where as a Procedure does not.
    4 What is Database Trigger ?
    A Database Trigger is procedure (set of SQL and PL/SQL statements) that is automatically executed as a result of an insert in,update to, or delete from a table.
    5 What is a Procedure ?
    A Procedure consist of a set of SQL and PL/SQL statements that are grouped together as a unit to solve a specific problem or perform a set of related tasks.
    6 What is a Package ?
    A Package is a collection of related procedures, functions, variables and other package constructs together as a unit in the database.
    7 What are the uses of Database Trigger ?
    Database triggers can be used to automatic data generation, audit data modifications, enforce complex Integrity constraints, and customize complex security authorizations.
    8 What are the advantages of having a Package ?
    Increased functionality (for example,global package variables can be declared and used by any proecdure in the package) and performance (for example all objects of the package are parsed compiled, and loaded into memory once)
    1 With which function of summary item is the compute at options required?
    percentage of total functions.
    2 Why is it preferable to create a fewer no. of queries in the data model?
    Because for each query, report has to open a separate cursor and has to rebind, execute and fetch data.
    3 Why is a Where clause faster than a group filter or a format trigger?
    Because, in a where clause the condition is applied during data retrieval than after retrieving the data.
    4 Which parameter can be used to set read level consistency across multiple queries?
    Read only.
    5 Which of the two views should objects according to possession?
    view by structure.
    6 Which of the above methods is the faster method?
    performing the calculation in the query is faster.
    7 Where is the external query executed at the client or the server?
    At the server.
    8 Where is a procedure return in an external pl/sql library executed at the client or at the server?
    At the client.
    9 When do you use data parameter type?
    When the value of a data parameter being passed to a called product is always the name of the record group defined in the current form. Data parameters are used to pass data to produts invoked with the run_product built-in subprogram.
    10 When a form is invoked with call_form, Does oracle forms issues a save point?
    Yes
    11 What are the important difference between property clause and visual attributes?
    Named visual attributes differ only font, color & pattern attributes, property clauses can contain this and any other properties. You can change the appearance of objects at run time by changing the named visual attributes programmatically , property clause assignments cannot be changed programmatically. When an object is inheriting from both a property clause and named visual attribute, the named visual attribute settings take precedence, and any visual attribute properties in the class are ignored.
    12 What use of command line parameter cmd file?
    It is a command line argument that allows you to specify a file that contain a set of arguments for r20run.
    13 What is WHEN-Database-record trigger?
    Fires when oracle forms first marks a record as an insert or an update. The trigger fires as soon as oracle forms determines through validation that the record should be processed by the next post or commit as an insert or update. c generally occurs only when the operators modifies the first item in the record, and after the operator attempts to navigate out of the item.
    14 What is use of term?
    The term file which key is correspond to which oracle report functions.
    15 What is trigger associated with the timer?
    When-timer-expired.
    16 What is the use of transactional triggers?
    Using transactional triggers we can control or modify the default functionality of the oracle forms.
    17 What is the use of place holder column?
    A placeholder column is used to hold calculated values at a specified place rather than allowing is to appear in the actual row where it has to appear.
    18 What is the use of image_zoom built-in?
    To manipulate images in image items.
    19 What is the use of hidden column?
    A hidden column is used to when a column has to embed into boilerplate text.
    20 What is the use of break group?
    A break group is used to display one record for one group ones. While multiple related records in other group can be displayed.
    21 What is the remove on exit property?
    For a modelless window, it determines whether oracle forms hides the window automatically when the operators navigates to an item in the another window.
    22 What is the purpose of the product order option in the column property sheet?
    To specify the order of individual group evaluation in a cross products.
    23 What is the maximum no of chars the parameter can store?
    The maximum no of chars the parameter can store is only valid for char parameters, which can be upto 64K. No parameters default to 23Bytes and Date parameter default to 7Bytes.
    24 What is the main diff. bet. Reports 2.0 & Reports 2.5?
    Report 2.5 is object oriented.
    25 What is the frame & repeating frame?
    A frame is a holder for a group of fields. A repeating frame is used to display a set of records when the no. of records that are to displayed is not known before.
    26 What is the difference between OLE Server & Ole Container?
    An Ole server application creates ole Objects that are embedded or linked in ole Containers ex. Ole servers are ms_word & ms_excel. OLE containers provide a place to store, display and manipulate objects that are created by ole server applications. Ex. oracle forms is an example of an ole Container.
    27 What is the difference between object embedding & linking in Oracle forms?
    In Oracle forms, Embedded objects become part of the form module, and linked objects are references from a form module to a linked source file.
    28 What is the difference between boiler plat images and image items?
    Boiler plate Images are static images (Either vector or bit map) that you import from the file system or database to use a graphical elements in your form, such as company logos and maps. Image items are special types of interface controls that store and display either vector or bitmap images. Like other items that store values, image items can be either base table items(items that relate directly to database columns) or control items. The definition of an image item is stored as part of the form module FMB and FMX files, but no image file is actually associated with an image item until the item is populate at run time.
    29 What is the difference between $$DATE$$ & $$DBDATE$$ $$DBDATE$$ retrieves the current database date $$date$$ retrieves the current operating system date.
    30 What is the diff. when Flex mode is mode on and when it is off?
    When flex mode is on, reports automatically resizes the parent when the child is resized.
    31 What is the diff. when confine mode is on and when it is off?
    When confine mode is on, an object cannot be moved outside its parent in the layout.
    32 What is the diff. bet. setting up of parameters in reports 2.0 reports 2.5?
    LOVs can be attached to parameters in the reports 2.5 parameter form.
    33 What is the advantage of the library?
    Libraries provide a convenient means of storing client-side program units and sharing them among multiple applications. Once you create a library, you can attach it to any other form, menu, or library modules. When you can call library program units from triggers menu items commands and user named routine, you write in the modules to which you have attach the library. When a library attaches another library, program units in the first library can reference program units in the attached library. Library support dynamic loading-that is library program units are loaded into an application only when needed. This can significantly reduce the run-time memory requirements of applications.
    34 What is term?
    The term is terminal definition file that describes the terminal form which you are using r20run.
    35 What is system.coordination_operation?
    It represents the coordination causing event that occur on the master block in master-detail relation.
    36 What is synchronize?
    It is a terminal screen with the internal state of the form. It updates the screen display to reflect the information that oracle forms has in its internal representation of the screen.
    37 What is strip sources generate options?
    Removes the source code from the library file and generates a library files that contains only pcode. The resulting file can be used for final deployment, but can not be subsequently edited in the designer. ex. f45gen module=old_lib.pll userid=scott/tiger strip_source YES output_file
    38 What is relation between the window and canvas views?
    Canvas views are the back ground objects on which you place the interface items (Text items), check boxes, radio groups etc.,) and boilerplate objects (boxes, lines, images etc.,) that operators interact with us they run your form . Each canvas views displayed in a window.
    39 What is pop list?
    The pop list style list item appears initially as a single field (similar to a text item field). When the operator selects the list icon, a list of available choices appears.
    40 What is new_form built-in?
    When one form invokes another form by executing new_form oracle form exits the first form and releases its memory before loading the new form calling new form completely replace the first with the second. If there are changes pending in the first form, the operator will be prompted to save them before the new form is loaded.
    41 What is lexical reference? How can it be created?
    Lexical reference is place_holder for text that can be embedded in a sql statements. A lexical reference can be created using & before the column or parameter name.
    42 What is forms_DDL?
    Issues dynamic Sql statements at run time, including server side pl/SQl and DDL
    43 What is difference between open_form and call_form?
    when one form invokes another form by executing open_form the first form remains displayed, and operators can navigate between the forms as desired. when one form invokes another form by executing call_form, the called form is modal with respect to the calling form. That is, any windows that belong to the calling form are disabled, and operators cannot navigate to them until they first exit the called form.
    44 What is bind reference and how can it be created?
    Bind reference are used to replace the single value in sql, pl/sql statements a bind reference can be created using a (:) before a column or a parameter name.
    45 What is an user exit used for?
    A way in which to pass control (and possibly arguments ) form Oracle report to another Oracle products of 3 GL and then return control ( and ) back to Oracle reports.
    46 What is an OLE?
    Object Linking & Embedding provides you with the capability to integrate objects from many Ms-Windows applications into a single compound document creating integrated applications enables you to use the features form .
    47 What is an object group?
    An object group is a container for a group of objects; you define an object group when you want to package related objects, so that you copy or reference them in other modules.
    48 What is an anchoring object & what is its use?
    An anchoring object is a print condition object which used to explicitly or implicitly anchor other objects to itself.
    49 What is a User_exit?
    Calls the user exit named in the user_exit_string. Invokes a 3Gl program by name which has been properly linked into your current oracle forms executable.
    50 What is a timer?
    Timer is an "internal time clock" that you can programmatically create to perform an action each time the timer expires.
    51 What is a Text_io Package?
    It allows you to read and write information to a file in the file system.
    52 What is a text list?
    The text list style list item appears as a rectangular box which displays the fixed number of values. When the text list contains values that can not be displayed, a vertical scroll bar appears, allowing the operator to view and select undisplayed values.
    53 What is a property clause?
    A property clause is a named object that contains a list of properties and their settings. Once you create a property clause you can base other object on it. An object based on a property can inherit the setting of any property in the clause that makes sense for that object.
    54 What is a physical page ? & What is a logical page ?
    A physical page is a size of a page. That is output by the printer. The logical page is the size of one page of the actual report as seen in the Previewer.
    55 What is a library?
    A library is a collection of subprograms including user named procedures, functions and packages.
    56 What is a difference between pre-select and pre-query?
    Fires during the execute query and count query processing after oracle forms constructs the select statement to be issued, but before the statement is actually issued. The pre-query trigger fires just before oracle forms issues the select statement to the database after the operator as define the example records by entering the query criteria in enter query mode. Pre-query trigger fires before pre-select trigger.
    57 What is a combo box?
    A combo box style list item combines the features found in list and text item. Unlike the pop list or the text list style list items, the combo box style list item will both display fixed values and accept one operator entered value.
    58 What does the term panel refer to with regard to pages?
    A panel is the no. of physical pages needed to print one logical page.
    59 What are visual attributes?
    Visual attributes are the font, color, pattern proprieties that you set for form and menu objects that appear in your application interface.
    60 What are three panes that appear in the run time pl/sql interpreter?
    1.Source pane. 2. interpreter pane. 3. Navigator pane.
    Regards
    B RANGARAJAN

  • ORACLE SERVER AND UNIX TP MONITOR-2

    제품 : ORACLE SERVER
    작성날짜 : 1995-01-24
    Subject: Oracle Server and UNIX Transaction Processing Monitors-2
    Page(3/4)
    This file contains commonly asked questions about Oracle7 Server and UNIX
    Transaction Processing Monitors (TPMs). The topics covered in this article are
         o Oracle Parallel Server and TP Monitors
         o Oracle and DCE-based TP Monitors
         o Other commonly asked questions
    The questions answered in part 3 provide additional detail to the information
    provided in part 1.
    Oracle Parallel Server and TP Monitors
    ======================================
    How does Oracle Parallel Server (OPS) work with TP Monitors?
    If you are using Oracle-managed transactions, there are no special
    considerations. But if you are using TPM-managed transactions, and
    thus need to use the XA interface, then Oracle requires release 7.1.3
    or later and a special version of the Distributed Lock Manager, called
    the session-based lock manager. This version of the DLM is not yet
    available for all platforms. To understand this restriction, let's take
    a look at one of the technical details of XA.
    The XA specification requires that the Resource Manager be able to
    move a transaction from one process to another, and even to be
    able to commit in a separate process. In Oracle, transactions are
    attached to sessions, so that means that we also have to be able to
    move sessions. Therefore, the session/transaction can't have any state
    which is tied to a particular process. The first generation distributed
    lock managers were all built to use the process id as the lock owner,
    which doesn't work for locks which need to move with the transaction.
    Oracle and DCE-based TP Monitors
    ================================
    How does Oracle interface to the Encina TP monitor? To CICS/6000? I've
    heard that they require OSF DCE facilities in order to run?
    Oracle interfaces to Encina and CICS/6000 just as it does to any other
    TP Monitor. The TP Monitor issues XA commands to control transactions, and
    Oracle executes the commands. Encina and CICS/6000 do use DCE features for
    their own operation. However, this use is transparent to the Oracle Server.
    What DCE facilities can Oracle products take advantage of when working with
    a DCE-based TP Monitor?
    The two most commonly mentioned DCE features which might be useful
    to Oracle users are multi-threading and security. We look at these in
    the subsequent questions in this section.
    Encina documentation suggests that a Resource Manager such as Oracle can
    be either single-threaded or multi-threaded? Which way is Oracle XA
    implemented?
    The Oracle XA implementation is single-threaded, as is any Oracle client.
    Within a single process, at most one thread can access Oracle at a time.
    Does that mean that only a single Encina application can access an instance
    of Oracle transactionally at any given moment?
    No. Oracle XA is only single-threaded within a single application server
    process. Multiple applications can access Oracle simultaneously using XA
    by using different application processes. Encina allows
    (1) serial reuse of a single server by different clients. There are
    two options for this. The server can use long term reservation
    but be defined to be in shared or concurrent access mode, which
    allows the server to be used by another client as soon as an RPC
    completes. Alternatively, the server can use default reservation
    and exclusive mode, which allows the server to be used by another
    client as soon as the current transaction ends.
    (2) concurrent execution by multiple servers, even if they are accessing
    the same Oracle database. These may be executing the same or different
    procedures.
    These two features should let you get as much concurrency as you need.
    Why isn't the Oracle XA library multi-threaded?
    The XA specification specifically states that its use of the phrase
    "thread of control" means a process. If an RM were to multi-thread its
    XA, it would be in violation of the specification. This restriction
    was put place in because at the time the specification was written,
    there were numerous thread packages: if the TM used one, the application
    another, and perhaps the RM yet a third, there's no way it could work.
    As threads standards settle down, the later versions of XA will probably
    relax this restriction.
    Will Oracle change if the XA specification changes?
    Very likely. The exact time frame will of course depend on the priority of
    all work items at that time.
    Does Oracle use DCE security via the TP Monitors?
    The integrity of the connection between a DCE TP Monitor client and DCE
    TP Monitor server is protected by the DCE security functionality.
    Theoretically, the TP Monitor could make the DCE-protected client security
    information available to Oracle. Unfortunately, there's no standard way
    for a TP Monitor to pass security information information to a Resource
    Manager such as Oracle. Oracle is leading an effort to extend the X/Open
    model to allow use of the security information provided by the Monitor.
    In the meantime, the basic DCE security features such as encryption are
    useful within TP Monitors.
    Effective use of DCE security would normally also mean that the security of
    the TP Monitor client be passed through the TP Monitor, through the Oracle
    client (application server), to the Oracle Server, and possibly on
    to other Oracle Servers through database links. The ability to transfer
    security information to other processes, called delegation, is missing
    in DCE version 1.0. DCE version 1.1, expected to emerge in late 1994,
    has some delegation features. Oracle is examining these features to see
    how they might be used.
    Are there any special considerations for CICS/6000?
    There are two:
    (1) It is inefficient to run without XA. CICS/6000 is designed to
    use XA. It uses XA so that the CICS server can log on to Oracle
    when it starts, after which it makes that Oracle connection available
    to any transaction it executes. If you don't use XA, the CICS server
    does not itself log on to Oracle so each transaction has to log on
    and log off - a very expensive mode of operation. Also, it is very
    un-cics-like in that the application does the log{on,off} and also
    commits - in a mainframe CICS database program CICS would implicitly
    do these operations. Oracle does not recommend this mode because of the
    performance penalty.
    (2) CICS servers are generic and dynamically load application modules.
    In order for these modules to access the Oracle connection made by
    CICS, the applications must be built with a shared object version of
    the Oracle libraries. This is an installation option on platforms which
    support CICS/6000 and other products using its architecture such as
    CICS 9000.
    Other commonly asked questions
    ==============================
    What other Resource Managers can be included in an Oracle XA transaction?
    Several other relational database vendors have an XA implementation
    available or in progress. There is an XA C-ISAM product from
    Gresham Telecomputing. There are also Resource Managers contained
    within some of the TP Monitors which can be coordinated in the same
    transaction. For example, CICS/6000 has VSAM files and other data
    stores, Encina has its RQS queuing system, and Tuxedo has its /Q queuing
    system.
    What is Recoverable Queuing Service (RQS) and how does it interoperate with
    Oracle7 and Encina? What about /Q?
    Recoverable Queuing Service is a feature provided by Encina which allows
    transactional, distributed queuing (enqueue/dequeue). Tuxedo has a similar
    product called /Q. Because these products are themselves coordinated by the
    TM component of the TP Monitor, their queue operations are atomically
    coordinated with with operations on XA Resource Managers such as Oracle7
    Server. That is, they can atomically put something on one of their queues
    and commit an Oracle transaction, then at some later time dequeue an
    entry atomically with doing some other Oracle transaction. The queue
    system guarantees that the message will not be lost or transmitted twice.
    Can I mix TP Monitor applications with standard Oracle7 Server applications?
    Yes, you can have existing Oracle applications connected to the database
    with alongside TPM applications against the same database. The TPM does
    not manage the whole database, just those transactions which are started
    by the TPM. The Oracle Server will properly handle concurrency control
    between the transactions managed by itself and those managed by the TPM.
    Is Oracle planning to change its tools to be more suitable for TP Monitors?
    With Oracle Procedure Builder 1.5, to be available with CDE2,
    Oracle will provide a foreign function interface that allows you to
    dynamically set up PL/SQL calls that access C functions. In other
    words, you can access C routines in Windows DLLs from within your
    PL/SQL procedures. This will allow PL/SQL under Windows easy access to
    TP Monitor APIs.
    Does Oracle7 Server itself use XA-compliant TPMs as the interface to
    foreign RMs?
    No, for this purpose Oracle Server uses the SQL*Connect products or the new
    Transparent and Procedural Gateway products.
    Does Oracle7 Server use XA to coordinate Oracle7-only distributed
    transactions?
    No, it uses an internal mechanism.
    Can database links be used with XA?
    If an Oracle7 database is running under XA, it can access other Oracle7
    databases through database links, with some restrictions. First, the
    access to the other database must use SQL*Net V2 and be running MTS.
    Second, it must currently be to another Oracle7 database. Assuming those
    restrictions, the Oracle 7 database can do distributed update to another
    Oracle 7 database by using a database link, whether it is started by an
    Oracle application or a TP Monitor application. The TPM will see Oracle
    as only a single RM, but Oracle7 will propagate all the transaction
    commands to the other database, including the two-phase commit. If
    the transaction is started by a TP Monitor application and is using XA,
    it can also update non-Oracle resources managed by the TPM. If it
    is started from an Oracle application, it can only include resources
    managed by Oracle.
    Here's a sample configuration:
    | TPM | | TPM |
    | client | | client |
    | |
    | |
    | TPM |
    | |
    | |
    | Oracle | Forms, Forms, | Oracle | | non-XA | | XA |
    | client | Plus, Plus, | client | | TPM | | TPM |
    --------- Pro, Pro, --------- | server | | server |
    | Financials, Financials, | |(note 1)| ----------
    | etc. etc. | ---------- |
    | | | |
    | SQL | SQL | SQL | XA
    | commit | commit | commit | commit
    | | | |
    | Oracle | | Oracle | | Oracle | | Oracle |
    | server | | server | | server | | server |
    | | | |
    | | | |
    | | | |
    | Database 1 | | Database 2 |
    | | | |
    | A | A
    | | dblink to database 1 | |
    | ------------------------------------ |
    | |
    dblink to database 2
    Note 1: Oracle will work having both XA and non-XA servers but some TPMs
    may have restrictions on this.
    Are multiple direct connections possible from a Pro* program?
    Using XA, you can not only specify multiple direct connections to Oracle7
    databases, you can also update them both in the SAME transaction. The
    way to do this is to use a precompiler feature called a named database.
    When you use a named database, you qualify the SQL statement with the
    database name. For example, you write EXEC SQL AT dbname UPDATE emp ....
    We have a complementary feature in the xa open string to let the user
    associate the name with a particular RM instance, called the DB clause.
    You will also want to use the SqlNet clause in the open string so you
    can give the two different SIDs. This clause does not require the use of
    the SQL*Net product, it is just a naming convention. For more information,
    see Oracle7 Server for UNIX Administrator's Reference Guide.
    Some TP Monitors may not support having multiple Resource Mangers in the
    same server; check with the TPM vendor.
    Is there any collateral available for XA or TP Monitors?
    Oracle At Work 52684.0692
    Oracle7 Server for UNIX Administrator's #A10324-1
    Reference Guide
    Guide to Oracle's Products and Services #A10560
    Oracle7 Server and CICS/6000               #A14200
    Where can I get more information on the DTP model?
    X/Open's address is
    X/Open company Ltd (Publications)
    P O Box 109
    Penn
    High Wycombe
    Bucks HP10 8NP
    Tel: +44 (0)494 813844
    Fax: +44 (0)494 814989
    Request
    G307 Distributed Transaction Processing: Reference Model Version 2
    X/Open Guide G307 ISBN 1-859120-19-9 28cm.44p.pbk.220g.11/93
    Page(4/4)
    This file contains commonly asked questions about Oracle Server and UNIX
    Transaction Processing Monitors (TPMs). The topics covered in this article are
         o Performance with Oracle Server and TP monitors
         o Performance using Oracle's XA Library
    The questions answered in part 4 provide additional detail to the information
    provided in part 1.
    Performance with Oracle Server and TP Monitors
    ==============================================
    I have heard that Transaction Processing Monitors (TPMs) will increase
    Oracle Server performance. Is this true?
    Several hardware and TPM vendors have made the claim that TPMs
    will increase RDBMS performance. This claim is based on TPC-A
    benchmarks. The key point to understand about TPC-A is that it
    requires, for every transaction-per-second, ten times that many
    users to be connected. For example, to get 600 TPS, you need 6000
    users. The next question will answer in more detail how the the
    three-tier architecture addresses this requirement, but first let's
    look more generally at what TP Monitors can and can't do to improve
    performance.
    TP Monitors can provide better performance:
    (1) When there are more than several hundred users connected.
         This is because of the TP Monitor's role in the three-tier
         architecture, described in the next question. In this
         architecture, terminal handling is offloaded to one or more
         separate machines, freeing up those cycles to do database work.
         Note that this does NOT mean that Oracle itself runs faster,
         just that we've given it more CPU cycles to use.
    (2) When, because of the high potential concurrency of requests,
         significant resource contention exists. Use of a TP Monitor can
         limit the degree of concurrency and thus reduce contention.
    TP Monitors can not provide better performance:
    (1) For existing applications. The applications must be designed
         to fit the TP Monitor architecture.
    (2) For applications which are highly interactive in their use of
         the database. These applications put many messages
         through the transport system, and the TP Monitor is not as
         efficient as SQL*Net for point-to-point communication.
    (3) For CPU intensive single-query decision support. When executing
         a single large command, Oracle query facilities work efficiently,
         especially with the use of Oracle Parallel Query, available in 7.1.
    How does the three-tier solution help TPC-A, or other situations with
    thousands of on-line users?
    The TPC-A test calls for a large number of users to produce a given
    result. In the high-end results we produced in June, 1992, for example,
    6150 terminals were simulated to produce 618 TPC-A transactions.
    Thus, terminal concentration accounts for a large portion of the total
    processing time used.
    First, let's look at how the Multi Threaded Server would work for
    this benchmark. In this case, there are many client processes,
    but only a few server processes, which handle client requests on a
    first-come first serve basis. When they are done with a request,
    they take another client's request.
    ORACLE7 CLIENT/SERVER ARCHITECTURE WITH MULTI THREADED SERVER
    | Client | | Server |
    | __________ |______________|_____ _____________ _____________ |
    | | Client | | SQL*Net | |_|Dispatcher | | | |
    | | Process| | | ____| Process |___| | |
    | |________| | | | __|___________| | | |
    |____________| | | | | | | | |
    | | | | | | Oracle7 | |
    ______________ | | | __|__|____ | Server | |
    | Client | | | | __|_|_____ | | | |
    | __________ | | | | | Shared | |____| | |
    | | Client | | SQL*Net | | | | Server |_|____| | |
    | | Process|_|______________|__| | | Process|_| | | |
    | |________| | | | |________| |___________| |
    |____________| | | |
    | | |
    ______________ | | |
    | Client | | | |
    | __________ | | | |
    | | Client | | SQL*Net | | |
    | | Process|_|______________|____| |
    | |________| | | |
    |____________| | |
    |_______________________________________|
    Client processes = N Dispatcher processes >= 1
    Shared server processes >= 1
    If there are 500 clients in this environment, there will be one or more
    dispatcher processes, dynamically tunable, and one or more shared
    server processes, dynamically tunable, on the server. The reduction
    in the total number of processes handled by the server system
    results in more processing time available for RDBMS activity. Thus
    higher RDBMS transaction throughput can be obtained on the
    server system.
    But the problem for the TPC-A, and for certain large customer
    configurations, is not the only ability of the Oracle Server to
    process transactions, but also the ability of the operating
    system to handle huge numbers of incoming connections.
    There is one incoming connection for each client. Most UNIX
    operating systems have a limit on how many such connections they can
    handle. Even if a particular operating system allows a large number of
    connections, each takes some amount of overhead to manage.
    In order to service all 6150 terminals, we selected a 3-tier hardware
    environment where the middle tier, using a TPM, acted as a terminal
    concentrator. The high-end TPC-A architecture looked like the following.
    The Application Servers, which contain the Pro*C statements used to
    perform the transaction also run on the terminal concentrator machine
    in order to offload as much work from the database serve as possible.
    They send the compiled SQL over SQL*Net to the Oracle7 Server processes.
    ORACLE7 TPS-A CLIENT/SERVER ARCHITECTURE
    | Client | | Terminal | | Server |
    | ________ | | Concentrator | | |
    | | Client | |TPM | | | |
    | | Process|_|_____|__ _____ | | |
    | |________| |Comm | | | | | | |
    |____________| | | | | | | |
    | |__| | | | |
    ____________ | | TPM | | | |
    | Client | | ___| | _______ | | ________ _______ |
    | ________ | | | | |_| |__|_______|__| Oracle | | | |
    | | Client | |TPM | | | | |Appl. | |SQL*Net| | Server |__| | |
    | | Process|_|_____|_| |_____| |Server | | | | Process| | | |
    | |________| |Comm | |_______| | | |________| | | |
    |____________| | | | | | |
    |_______________________| | | | |
    | | | |
    ____________ _______________________ | |Oracle7| |
    | Client | | Terminal | | |Server | |
    | ________ | | Concentrator | | | | |
    | | Client | |TPM | | | | | |
    | | Process|_|_____|__ _____ | | __________ | | |
    | |________| |Comm | | | | _______ |SQL*Net| | Oracle | | | |
    |____________| | | | |_| |__|_______|__| Server |__| | |
    | |__| | |Appl. | | | | Process| | | |
    ____________ | | TPM | |Server | | | |________| |_______| |
    | Client | | ___| | |_______| | | |
    | ________ | | | | | | | |
    | | Client | |TPM | | | | | | |
    | | Process|_|_____|_| |_____| | | |
    | |________| |Comm | | | |
    |____________| | | | |
    |_______________________| |________________________|
    Clients = 6150 Terminal concentrators = 17
    TP Monitor instances = 17
    Application server processes Oracle Server processes
    = 17*8 = 17*8
    The TPM is the software component of the terminal concentrator. In this role
    it offloads terminal handling from the the machine running Oracle Server.
    Since more than one terminal concentrator can be configured, whereas the
    database in this case had to run on a single machine, concentrator machines
    can be added until the performance of the back-end machine was optimized.
    This three-tier solution resulted in the outstanding transaction throughput
    announced with Oracle7 Server. Even with Oracle Parallel Server, it may pay
    to offload the terminal handling so that the cluster can be exclusively used
    for database operations.
    Can you summarize the performance discussion for me?
    Depending on the number of users required, different architectures may be
    used in a client/server environment to maximize performance:
    1) For a small number of users, the traditional Oracle two-task
    architecture can be used. In this case, there is a one-to-one
    correspondence between client processes and server processes. It's
    simple, straightforward, and efficient.
    2) For a large number of users, Multi Threaded Server might be a better
    approach. Although some tuning may be required, Multi Threaded Server
    can handle a relatively large number of users for each machine size
    compared to the traditional Oracle approach. Using this approach,
    customers will be able to handle many hundreds of users on many
    platforms. Furthermore, current Oracle applications can move to this
    environment without change.
    3) For a very large number of users, where transactions are simple and
    terminal input concentration is the overriding performance issue, a
    3-tier architecture incorporating a TPM may be useful. In this case,
    terminal concentration is handled by the TPM in the middle tier. As
         you might expect, it is a more complex environment requiring more
         system management. For existing Oracle customers, significant Oracle
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