Oracle SELECT and storage technique

Hi,
I have 2 questions please. First of all, what kind of storage mechanism is used in Oracle e.g Oracle 11g, is it HEAP BASED or some other?
Actually I am not able to search how Oracle stores the data into tables as I've heard that heap based storage is a mechanism in which the data is saved in the same order as it is being inserted?
What is the Linear Search?
I've performed test on more than 40 tables with simple SELECT and Elapsed time is always favoring 16k block size when compared to 4k and 8k data block size.
Just thinking the reason that why SELECT is favoring 16k in all the tests, because the data is saved in hundreds and thousands of data blocks and if it is in the smaller data block, it has to go and search more and more data blocks, is it true?
Please help me with your expert opinions and if possible please suggest me some book or paper which explains the ORACLE STORAGE MECHANISM AND SEARCHING MECHANISM i.e. LINEAR search or what?
I'll appreciate the suggestions.
Thanks a lot.
Best Regards,
John

John-M wrote:
I see you've also re-opened an older question which overlaps with this topic - so I'll be making some comments there as well: Re: single col v/s multi col table elapsed time comparison
I have 2 questions please. First of all, what kind of storage mechanism is used in Oracle e.g Oracle 11g, is it HEAP BASED or some other?
The most commonly used mechanism is heap-based - rows are put wherever the next convenient space happens to be.
Actually I am not able to search how Oracle stores the data into tables as I've heard that heap based storage is a mechanism in which the data is saved in the same order as it is being inserted?
Not quite - but see other post.
What is the Linear Search? Depends how technical you want to be - the implication is that you "start at the beginning, work through to the end and then stop". The search it linear because the time it takes to complete it proportional with the volume of data available.
>
Please help me with your expert opinions and if possible please suggest me some book or paper which explains the ORACLE STORAGE MECHANISM AND SEARCHING MECHANISM i.e. LINEAR search or what?
The Concepts manual is pretty good on storage.
Regards
Jonathan Lewis

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    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?
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    Marc Prud'hommeaux [email protected]
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    Edited by: user12024904 on 28-Oct-2011 04:05

    Hi,
    Our Oracle DB and Gateway are running on the following system:
    HP-UX B.11.31 U ia64
    The following SQL code is executed in SQLPlus:
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    AND START_TIME <= to_date('2010-10-22 00:00:00','rrrr-mm-dd hh24:mi:ss')
    AND IP_ADDRESS = '127.0.0.1';
    Gateway debug trace shows the following:
    Oracle Corporation --- TUESDAY NOV 01 2011 14:59:15.254
    Heterogeneous Agent Release
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    Oracle Corporation --- TUESDAY NOV 01 2011 14:59:15.254
    Version 11.2.0.2.0
    HOSGIP for "HS_FDS_TRACE_LEVEL" returned "ON"
    HOSGIP for "HS_FDS_SHAREABLE_NAME" returned "/usr/local/greenwich64/lib/libodbc.so.1"
    HOSGIP for "HS_OPEN_CURSORS" returned "50"
    HOSGIP for "HS_FDS_FETCH_ROWS" returned "100"
    HOSGIP for "HS_LONG_PIECE_TRANSFER_SIZE" returned "65536"
    HOSGIP for "HS_NLS_NUMERIC_CHARACTER" returned ".,"
    HOSGIP for "HS_KEEP_REMOTE_COLUMN_SIZE" returned "OFF"
    HOSGIP for "HS_FDS_DELAYED_OPEN" returned "TRUE"
    HOSGIP for "HS_FDS_WORKAROUNDS" returned "0"
    HOSGIP for "HS_FDS_MBCS_TO_GRAPHIC" returned "FALSE"
    HOSGIP for "HS_FDS_GRAPHIC_TO_MBCS" returned "FALSE"
    HOSGIP for "HS_FDS_RECOVERY_ACCOUNT" returned "RECOVER"
    HOSGIP for "HS_FDS_TRANSACTION_LOG" returned "HS_TRANSACTION_LOG"
    HOSGIP for "HS_FDS_TIMESTAMP_MAPPING" returned "DATE"
    HOSGIP for "HS_FDS_DATE_MAPPING" returned "DATE"
    HOSGIP for "HS_FDS_MAP_NCHAR" returned "TRUE"
    HOSGIP for "HS_FDS_RESULTSET_SUPPORT" returned "FALSE"
    HOSGIP for "HS_FDS_RSET_RETURN_ROWCOUNT" returned "FALSE"
    HOSGIP for "HS_FDS_PROC_IS_FUNC" returned "FALSE"
    HOSGIP for "HS_FDS_REPORT_REAL_AS_DOUBLE" returned "FALSE"
    using query as default value for "HS_FDS_DEFAULT_OWNER"
    HOSGIP for "HS_SQL_HANDLE_STMT_REUSE" returned "FALSE"
    SQL text from hgopars, id=1, len=117 ...
    00: 53454C45 43542022 454E445F 54494D45 [SELECT "END_TIME]
    10: 222C2249 505F4144 44524553 53222C22 [","IP_ADDRESS","]
    20: 53544152 545F5449 4D452220 46524F4D [START_TIME" FROM]
    30: 20224950 5F414343 5F434F4D 504C4554 [ "IP_ACC_COMPLET]
    40: 45222057 48455245 20224950 5F414444 [E" WHERE "IP_ADD]
    50: 52455353 223D2731 32372E30 2E302E31 [RESS"='127.0.0.1]
    60: 2720414E 44202253 54415254 5F54494D [' AND "START_TIM]
    70: 45223C3D 3F [E"<=?]
    Deferred open until first fetch.
    Performing delayed open.
    The non-Oracle DB is CopperEye Retrieval Server with its own custom ODBC driver.
    CopperEye query log shows that the following query is received from Oracle Gateway:
    01/11/2011 14:26:31 - NEW QUERY :
    SELECT "END_TIME","IP_ADDRESS","START_TIME" FROM "IP_ACC_COMPLETE" WHERE "IP_ADDRESS"='127.0.0.1' AND "START_TIME"<=?
    which complies with the information in Oracle Gateway trace file.
    So, it seems that it's Oracle DB decision to split the original WHERE clause into two parts, delegate one part to the remote site, retrieve the data and then apply the remaining filter locally.

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