Advanced Queueing and databases synchronization

What kind of (application) problems could be solved by Advanced Queueing ?
What about databases synchronization ( two Oracle Database Standard Edition One ) ?
TANK YOU !

AQ is intended for messaging. Messaging between applications, messaging between back-end and front-end.
Synchronization would be a poor use of messaging. If you want synchronization then name your version number (all four places) and replication technology and we can point you in the right direction.
For most situations I use:
DBMS_RECTIFIER_DIFF or DBMS_COMPARISON
http://www.morganslibrary.org/library.html

Similar Messages

Advanced Queueing and Propagation

Hi all,
I am trying to propagate messages from one queue to another in the same database.
For this I am using DBMS_AQADM. The code is as under.
CREATE OR REPLACE TYPE event_msg_type_surya AS OBJECT (
name VARCHAR2(10),
current_status NUMBER(5),
next_status NUMBER(5)
begin
DBMS_AQADM.create_queue_table (
queue_table => 'system.queue_tab_consumer',
queue_payload_type => 'system.event_msg_type_surya');
end;
begin
DBMS_AQADM.create_queue (
queue_name => 'system.queue_consumer',
queue_table => 'system.queue_tab_consumer');
end;
begin
DBMS_AQADM.start_queue (
queue_name => 'system.queue_consumer',
enqueue => TRUE);
end;
begin
DBMS_AQADM.create_queue_table (
queue_table => 'system.queue_tab_producer',
queue_payload_type => 'system.event_msg_type_surya',
multiple_consumers => TRUE);
end;
begin
DBMS_AQADM.create_queue (
queue_name => 'system.queue_producer',
queue_table => 'system.queue_tab_producer');
end;
begin
DBMS_AQADM.start_queue (
queue_name => 'system.queue_producer',
enqueue => TRUE);
end;
BEGIN
dbms_aqadm.add_subscriber (
queue_name => 'system.queue_producer',
subscriber => sys.aq$_agent('SYSTEM','system.queue_consumer',null)
END;
BEGIN
dbms_aqadm.schedule_propagation(
queue_name => 'system.queue_producer',
latency => 0
END;
begin
DBMS_AQADM.ALTER_PROPAGATION_SCHEDULE(
queue_name => 'system.queue_producer',
duration => '2000',
next_time => 'SYSDATE + 1/1440',
latency => '32');
end;
As per the expectation if producer_queue is populated the messages must get propagated to consumer_queue.But this is not getting done even after waiting long hours.
Can anyone throw any light on this.
Any help will be greatly appreciated.
Thanks in advance.

I am also looking for some examples of using SQL/PLSQL w/Advanced Queueing. We currently have the following scenario: One server has non-relational tables; another server has relational tables which house the same data in a relational format. We are looking for a way to migrate the non-relational data to the relational tables and keep the data updated when it changes in the non-relational tables.
We had considered using materialized views, but, this was ruled out because the non-relational tables are created and dropped on a daily basis.
My email: [email protected]
Thanks for any input you may have!

Advanced Queueing and SQL in same transaction?

Can Advanced Queueing operations and SQL operations be combined in one atomic transaction? I can't find any reference to this in the Oracle AQ documentation and none of the examples show this. In my application I'm having problems that seem like deadlock when I do combine AQ and SQL in the same transaction. However, when I place them in seperate transactions it works.
null

I am also looking for some examples of using SQL/PLSQL w/Advanced Queueing. We currently have the following scenario: One server has non-relational tables; another server has relational tables which house the same data in a relational format. We are looking for a way to migrate the non-relational data to the relational tables and keep the data updated when it changes in the non-relational tables.
We had considered using materialized views, but, this was ruled out because the non-relational tables are created and dropped on a daily basis.
My email: [email protected]
Thanks for any input you may have!

Deadlock using Advanced Queueing and OC4J

We develop an application which extensively uses JMS. We use Advanced Queueing as JMS provider (Oracle9i 9.2.0.3.0 and OC4J 9.0.3). In our application we have message driven bean which listens on cerain queue and can send messages to other queues/topics as a result of processing received message. In this scenario we sometimes get a java-level deadlock.
An example of such deadlock is here (taken from thread dump, jvm is sun 1.4.1_01):
Found one Java-level deadlock:
=============================
"TaskManager":
waiting to lock monitor 0x8ff45c (object 0x39db898, a oracle.jdbc.driver.OracleCallableStatement),
which is held by "ApplicationServerThread-1"
"ApplicationServerThread-1":
waiting to lock monitor 0x8ff43c (object 0x39e4de8, a oracle.jdbc.driver.OracleConnection),
which is held by "TaskManager"
Java stack information for the threads listed above:
===================================================
"TaskManager":
at oracle.jdbc.driver.OracleCallableStatement.close(OracleCallableStatement.java:980)
- waiting to lock <039DB898> (a oracle.jdbc.driver.OracleCallableStatement)
- locked <039E4DE8> (a oracle.jdbc.driver.OracleConnection)
at oracle.jdbc.driver.OracleConnection.close_statements(OracleConnection.java:2333)
- locked <039E4DE8> (a oracle.jdbc.driver.OracleConnection)
at oracle.jdbc.driver.OracleConnection.close(OracleConnection.java:1412)
- locked <039E4DE8> (a oracle.jdbc.driver.OracleConnection)
at com.evermind.sql.DriverManagerPooledConnection.close(DriverManagerPooledConnection.java:247)
- locked <039DC320> (a com.evermind.sql.DriverManagerPooledConnection)
at com.evermind.sql.OrionPooledDataSource.removeCache(OrionPooledDataSource.java:559)
- locked <08A67AF0> (a com.evermind.sql.OrionPooledDataSource)
at com.evermind.sql.OrionPooledDataSource.run(OrionPooledDataSource.java:505)
at com.evermind.sql.DriverManagerXADataSource.run(DriverManagerXADataSource.java:195)
at com.evermind.util.TaskManager.run(TaskManager.java:181)
at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(PooledExecutor.java:797)
at java.lang.Thread.run(Thread.java:536)
"ApplicationServerThread-1":
at oracle.jdbc.driver.OracleConnection.getDescriptor(OracleConnection.java:2549)
- waiting to lock <039E4DE8> (a oracle.jdbc.driver.OracleConnection)
at oracle.sql.StructDescriptor.createDescriptor(StructDescriptor.java:132)
at oracle.jpub.runtime.MutableStruct.toDatum(MutableStruct.java:128)
at oracle.jms.AQjmsObjectMessage_C.toDatum(AQjmsObjectMessage_C.java:45)
at oracle.jdbc.driver.OraclePreparedStatement.setORAData(OraclePreparedStatement.java:2700)
- locked <039DB898> (a oracle.jdbc.driver.OracleCallableStatement)
at com.evermind.sql.OrclCallableStatement.setORAData(OrclCallableStatement.java:732)
at oracle.jms.AQjmsProducer.enqueue(AQjmsProducer.java:837)
- locked <091DBC40> (a oracle.jms.AQjmsProducer)
at oracle.jms.AQjmsProducer.publish(AQjmsProducer.java:1366)
- locked <091DBC40> (a oracle.jms.AQjmsProducer)
at oracle.jms.AQjmsProducer.publish(AQjmsProducer.java:1216)
- locked <091DBC40> (a oracle.jms.AQjmsProducer)
at com.abilitydev.slovalco.jms.dispatcher.alarm.AlarmMessageDispatcher.dispatchMessage(AlarmMessageDispatcher.java:229)
at com.abilitydev.slovalco.jms.dispatcher.DispatcherWrapper.dispatchMessage(DispatcherWrapper.java:51)
at com.abilitydev.slovalco.jms.dispatcher.DispatcherWrapper.dispatchMessage(DispatcherWrapper.java:49)
at com.abilitydev.slovalco.jms.dispatcher.DispatcherWrapper.dispatchMessage(DispatcherWrapper.java:49)
at com.abilitydev.slovalco.jms.dispatcher.DispatcherWrapper.dispatchMessage(DispatcherWrapper.java:49)
at com.abilitydev.slovalco.jms.handlers.PotDataHandler.handleMessage(PotDataHandler.java:40)
at com.abilitydev.slovalco.jms.ObjectMessageBean.onMessage(ObjectMessageBean.java:95)
at com.evermind.server.ejb.MessageDrivenBeanInvocation.run(MessageDrivenBeanInvocation.java:141)
at com.evermind.server.ejb.MessageDrivenHome.onMessage(MessageDrivenHome.java:769)
at com.evermind.server.ejb.MessageDrivenHome.run(MessageDrivenHome.java:929)
at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(PooledExecutor.java:797)
at java.lang.Thread.run(Thread.java:536)
Any suggestions?
Thanks, Marcel

Marcel --
This sounds like something that you'd want to pursue with the Oracle support folks.
Is it possible for you to test the application using the OC4J 904 Developer Preview and see if the problem reproduces?
btw -- are you using a tool to pull the information from the thread-dump? I noticed the line "Found one Java-level deadlock:" which looks like output from a tool. Just interested that's all.
cheers
-steve-

Plz Help!!! Urgent Mobile Database and database synchronization

Have any one heard of Funambol? I would like to create a mobile database to be sync with server everyday to update daily task... Is Funambol is the solution for this? Or is there any solution??

Have any one heard of Funambol? I would like to
create a mobile database to be sync with server
everyday to update daily task... Is Funambol is the
solution for this? Or is there any solution??funambol supports for contacts,email ..synchronisation
these are applications which are already in your mobile phone
they use syncml to support this
you need to have funambol server
the process is you embedd your data in syncml
and send it to server which will update your server database
as far as relation database is concerened i fear they haven't implemented any software for it
you can check there website
and they say it can be done
you need to start from scratch i think
and you have to learn all syncml and it's code it's time consuming
depending upon your requirement and time you can decide for some alternative
www.funambol.com

Data synchronization between apps using Advanced Queueing

Dear you,
I'm quite new to Oracle Advanced Queueing and looking at this for using now.
I want to integrate our system (name A, Web application with Java technology, deployed on Ora AS 10g, using Oracle database) with an outside system (named B, .NET technology, using Sybase database) using Oracle Advanced Queuing.
Could you please suggest the interfaces for both system A & B to access Advanced Queuing? What is the best to use: Java, JMS or HTTP/HTTPS/SMTP?
Many thanks,
K.N

So we are talking EPMA Data Synchronization here.
Are you able to limit decimal precision?
The number provided in the error message is not negative -- can you please provide more details?
Thank you,
Todd Rebner

ABAP AND DATABASES

Hi Experts..
I would like to know how to create a databases in SQL and have access from ABAP.. to Modify, Consult and do the basic operations like insert information, drop and modify in the respective tables.
I'm ussing MiniSap Minigui 6.2 on Windows XP and the BCUSER
Thank you very much for your help
REGARDS

HI Araceli,
Database Access using Advanced Business Application Programming (ABAP)
Basics :
Accessing the Database in the R/3 System is performed through the interface provided by the SAP System, which in the SAP System is referred to as the Database Interface. A user can access the database from his/her program through Open SQL and Native SQL depending upon the circumstances.
About SQL
The Structured Query Language (SQL) is a largely standardized language, which is used for accessing relational databases. It can be divided as follows:
Data Manipulation Language (DML)
These statements are for reading and changing data in database tables.
Data Definition Language (DDL)
These statements are for creating and administering database tables.
Data Control Language (DCL)
These statements are used for authorization and consistency checks.
So each database has a programming interface. This programming interface allows the user to access the database tables by using SQL statements. But, these SQL statements in the programming interfaces are not fully standardized. So, you must refer to the documentation of that system for a list of the SQL statements available and also their correct syntax in order to access a specific database system.
Interface thru data base
Each work process on an application server must have a database interface if you want to make the R/3 system independent of the database system, and also to use it correctly despite the differences in the SQL syntax between various databases. By means of this interface only, the R/3 system can communicate with the database. All of the database requests from the R/3 system are converted into the correct Standard SQL statements for the database system by the database interface. In order to perform this function, it has to use a database-specific component, which shields the differences between database systems from the rest of the database interface. You have to choose the appropriate layer when installing the R/3 system. A user can access a database from a program through Open SQL and Native SQL.
Open SQL
Open SQL are statements that make up a subset of Standard SQL which is fully integrated in ABAP. Open SQL consists of Data Manipulation Language (DML) which is a part of Standard SQL.
One of the ways to access the database from a program is Open SQL. These Open SQL statements are nothing but a subset of Standard SQL, which is fully integrated in ABAP. Irrespective of which database system the R/3 installation is using, they allow you to access data. When I said that, Open SQL consists of the Data Manipulation Language (DML). I meant that it allows you to read (i.e. to SELECT) and change (For example to INSERT, UPDATE, DELETE) data.
Moreover, Open SQL also goes beyond Standard SQL. This is to provide statements that can simplify or speed up database access in conjunction with other ABAP constructions. Apart from that, it also gives you the freedom to buffer certain tables on the application server, thereby enabling you to save excessive database access. In this case, the database interface is responsible for comparing the buffer with the database. As far as buffer storage is concerned, they may be stored in two parts: the working memory of the current work process, and the shared memory for all work processes on an application server. The data in the various buffers is synchronized at set intervals by buffer management where an R/3 system is distributed across more than one application server. It should be noted that data in the buffer is not always up to date when you are buffering the database. That is why you should only use the buffer for data which does not change often. You can specify whether a table can be buffered in its definition in the ABAP Dictionary.
Open SQL consists of a set of ABAP statements. These statements perform operations on the central database in the R/3 system. The results of the operations and any error messages which come out of it are independent of the current database system. Thus, uniform syntax and semantics for all of the database systems supported by SAP is provided by Open SQL. Regardless of the current database system, the ABAP programs, which use Open SQL statements only, will work in any R/3 system. Moreover, Open SQL statements work only with database tables that have been created in the ABAP Dictionary.
You have the freedom to combine columns belonging to different database tables to a database view (or view for short) in the ABAP Dictionary. Views are also handled in exactly the same way as database tables in Open SQL statements.
Some Open SQL keywords are as follows:
SELECT - It reads data from database tables.
INSERT - It adds rows to database tables.
UPDATE - It changes the contents of rows of database tables.
MODIFY - It inserts rows into database tables or changes the content of existing rows.
DELETE - It deletes rows from database tables.
OPEN CURSOR, FETCH, CLOSE CURSOR - It reads rows of database tables using the cursor.
Return Codes
The following two system fields are filled with return codes by all Open SQL statements:
SY-SUBRC: The system field SY -SUBRC contains the value 0 after every Open SQL statement if the operation was successful. When a value is other than 0, then it is unsuccessful.
SY-DBCNT: The system field SY-DBCNT contains the number of database lines processed after an open SQL statement.
Native SQL
The other possible way to access the database from a program is Native SQL. It is only loosely integrated into ABAP. It allows access to all of the functions contained in the programming interface of the respective database system. Native SQL statements are not checked and converted as compared to Open SQL statements. Unlike Open SQL, these are sent directly to the database system. The function of the database-dependent layer remains minimal when you use Native SQL. The Programs which use Native SQL are written specifically for a database system. You should avoid using Native SQL wherever possible when writing R/3 applications. However, you can use it in some parts of the R/3 Basis System, for instance, for creating or changing table definitions in the ABAP Dictionary.
Regardless of the database platform that your R/3 system is using, Open SQL allows you to access database tables, which are declared in the ABAP Dictionary. Native SQL allows you to use database specific SQL statements in an ABAP program. This means that you can use database tables that are not administered by the ABAP Dictionary. Aside from that, you can also integrate data that is not part of the R/3 system.
As a rule, an ABAP program that contains database-specific SQL statements will not run under different database systems. You have to use Open SQL statements only, if your program is used on more than one database platform.
You must proceed with the EXEC SQL statement, and follow the ENDEXEC statement to use a: Native SQL statement. For example
Listing 1
EXEC SQL [PERFORMING
ENDEXEC.There is no period after Native SQL statements. Also, using quotation marks (") or an asterisk (*) at the beginning of a native SQL statement's line does not introduce a comment as it would in normal ABAP syntax. You need to know if the table and field names are case-sensitive in your chosen database.
The data is transported between the database table and the ABAP program using host variables in Native SQL statements. These are preceded in a Native SQL statement by a colon ( and are declared in the ABAP program. The elementary structures can be used as host variables. The structures of an INTO clause are treated exceptionally, as though all of their fields are listed individually. If the selection in a Native SQL SELECT statement is a table, then you can pass it to ABAP line by line using the PERFORMING addition. For each line read, the program calls a subroutine
. Further, you can process the data within the subroutine.
After the ENDEXEC statement, SY-DBCNT contains the number of lines processed as it does in Open SQL. In almost all cases, SY-SUBRC contains the value a after the ENDEXEC statement. Cursor operations form an exception: after FETCH, SY-SUBRC is 4 if no more records could be read. This is also applied when you read a result set using EXEC SQL PERFORMING.
Native SQL Scope
Native SQL is very important as it allows you to execute nearly all available statements through the SQL programming interface (usually known as SQL Call Interface or similar) for directly executing SQL program code (using EXEC IMMEDIATE or a similar command). The statements that are not supported are listed in the following section:
·         Native SQL and the Database Interface,
·         Native SQL and Transactions
·         Native SQL and the Database Interface
Native SQL statements bypass the R/3 database interface. With the database buffer on the application server, there is no table logging, and no synchronization. Therefore, you should use Open SQL to change database tables declare in the ABAP dictionary wherever possible. Since the columns contain extra database specific length information for the column tables declared in the ABAP dictionary, containing long columns with the type LCHAR or LRAW should only be addressed using Open SQL. Native SQL may not produce the correct result, as it does not take this information into account. Native SQL does not support automatic client handling. Instead, you must treat a client field like any other field
Native SQL and Transactions
One should not use any transaction control statement such as COMMIT, ROLLBACK WORK, or any statements that set transaction parameters using Native SQL to ensure that transaction in the R/3 System are consistent.
ABAP Dictionary
The ABAP Dictionary is nothing but a part of the ABAP Workbench. It allows you to create and administer database tables. There are no statements from the DDL part of Standard SQL in Open SQL. It should be noted that normal application programs should not create or change their own database tables.
To create and change database tables, the ABAP Dictionary has to use the DDL part of Open SQL. Besides this, it also administers the ABAP Dictionary in the database. In addition, the ABAP Dictionary contains meta-descriptions of all database tables in the R/3 system. Here, only database tables appears in the Dictionary, which you have created using the ABAP Dictionary. Open SQL statements can only access tables, which exists in the ABAP Dictionary.
Authorization and Consistency Checks
With regard to authorization and consistency checks, the DCL part of Standard SQL is not used in R/3 programs. Whereas, the work processes which are within the R/3 system are logged into the database system as users with full rights. By using the R/3 authorization concept, the authorizations of programs or users to read or change database tables is administered within the R/3 system. In addition, transactions must equally ensure their own data consistency using the R/3 locking concept.
The R/3 lock concept allows you to monitor your system with regards to lock logics. The R/3 lock concept works closely together with the R/3 updates.
As an example, say that a travel agent wants to book a flight for a customer who wants to fly to a particular city with a certain airline on a certain day. If there are still available seats on the flight, then the booking will be possible, otherwise it will lead to overbooking. Hence, the database entry corresponding to the flight must be locked against access from other transactions to avoid the possibility of overbooking. This is because two agents might both be doing this same thing at the same time, and we need to make sure that we don't overbook.
Lock Mechanisms
When the database system receives change statements (INSERT, UPDATE, MODIFY, DELETE) from a program, it automatically sets database locks. Database locks are locks on the database entries affected by statements to prevent problems. Since the lock mechanism uses a, lock flag in the entry, you can only set a lock for an existing database entry. After each database commit, these flags are automatically deleted. This means that database locks can never be set for longer than a single database LUW, a single dialog step in an R/3 application program.
Therefore, physical locks in the database system are insufficient for the requirements of an R/3 transaction. Locks in the R/3 system must remain set for the duration of a whole SAP LUW, that is, over several dialog steps. They must also be capable of being handled by different work processes and application servers. As a result, each lock must apply on all servers in that R/3 system.
Database Accesses of the NetWeaver AS ABAP
The NetWeaver AS ABAP stores long-term data in a central relational database table. In a relational database model, the real world is represented by tables. A table is a two-dimensional matrix, consisting of lines and columns (fields). The smallest possible combination of fields that can uniquely identify each line of the table is called the key. Each table must have at least one key, and each table has one key that is defined as its primary key. Relationships between tables are represented by foreign keys.
Standard SQL
SQL (Structured Query Language) is a largely standardized language for accessing relational databases. It can be divided into three areas:
·        Data Manipulation Language (DML)
Statements for reading and changing data in database tables.
·        Data Definition Language (DDL)
Statements for creating and administering database tables.
·        Data Control Language (DCL)
Statements for authorization and consistency checks.
Each database has a programming interface that allows you to access the database tables using SQL statements. The SQL statements in these programming interfaces are not fully standardized. To access a specific database system, you must refer to the documentation of that system for a list of the SQL statements available and their correct syntax.
The Database Interface
To avoid incompatible situations between different database tables and to make the NetWeaver AS ABAP system independent of the database system in use, each work process on an ABAP application server contains a database interface. The NW AS communicates with the database solely through the database interface. The database interface converts all of the database requests from the NW AS into the correct Standard SQL statements for the database system in use. To do this, it uses a database-specific component that shields the differences between database systems from the rest of the database interface. You choose the this component when you install NetWeaver AS ABAP in accordance with the database in use.
ABAP programs have two options for accessing the database interface: Open SQL and Native SQL.
Open SQL
Open SQL statements are a fully integrated subset of Standard SQL within ABAP. They enable the ABAP programs to access data irrespective of the database system installed. Open SQL consists of the Data Manipulation Language (DML) part of Standard SQL; in other words, it allows you to read (SELECT) and change (INSERT, UPDATE, DELETE) data.
Open SQL also goes beyond Standard SQL to provide statements that, in conjunction with other ABAP constructions, can simplify or speed up database access. It also allows you to buffer certain tables on the application server, saving excessive database access. In this case, the database interface is responsible for comparing the buffer with the database. Buffers are partly stored in the working memory of the current work process, and partly in the shared memory for all work processes on an application server. In SAP systems that are distributed across more than one application server, the data in the various buffers is synchronized at set intervals by buffer management. When buffering the database, you must remember that data in the buffer is not always up to date. For this reason, you should only use the buffer for data which does not often change. You specify whether a table can be buffered in its definition in the ABAP Dictionary.
Native SQL
Native SQL is only loosely integrated into ABAP, and allows access to all of the functions contained in the programming interface of the respective database system. Unlike Open SQL statements, Native SQL statements are not checked and converted, but instead are sent directly to the database system. When you use Native SQL, the function of the database-dependent layer is minimal. Programs that use Native SQL are specific to the database system for which they were written. When developing generally valid ABAP applications, you should as far as possible avoid using Native SQL. In some components of the SAP System, Native SQL is used for example, in the ABAP Dictionary for creating or changing tables.
The ABAP Dictionary
The ABAP Dictionary, part of the ABAP Workbench, allows you to create and administer database tables. Open SQL contains no statements from the DDL part of Standard SQL. Normal application programs should not create or change their own database tables.
The ABAP Dictionary uses the DDL part of Open SQL to create and change database tables. It also administers the ABAP Dictionary in the database. The ABAP Dictionary contains meta descriptions of all database tables in the NetWeaver AS ABAP system. Only database tables that you create using the ABAP Dictionary appear in the Dictionary. Open SQL statements can only access tables that exist in the ABAP Dictionary.
Authorization and Consistency Checks
The DCL part of Standard SQL is not important in ABAP programs. The work processes within the ABAP application server are logged on to the database system as users with full authorization. The authorizations of programs or program users to read or change database tables is managed by the authorization concept. Equally, transactions must ensure their own data consistency in the database using the SAP locking concept. For more information, refer to the chapter Data Consistency.
Work Processes
Work processes execute the individual dialog steps of ABAP application programs. They are components of ABAP application servers. The next two sections describe firstly the structure of a work process, and secondly the different types of work process in NetWeaver AS ABAP.
Structure of a Work Process
The following diagram shows the components of a work process:
Screen Processor
In ABAP application programming, there is a difference between user interaction and processing logic. From a programming point of view, user interaction is controlled by screens. As well as the actual input mask, a screen also consists of flow logic, which controls a large part of the user interaction. NetWeaver AS ABAP contains a special language for programming screen flow logic. The screen processor executes the screen flow logic. Via the dispatcher, it takes over the responsibility for communication between the work process and the SAPgui, calls modules in the flow logic, and ensures that the field contents are transferred from the screen to the flow logic.
ABAP Processor
The actual processing logic of an application program is written in ABAP - SAPs own programming language. The ABAP processor executes the processing logic of the application program, and communicates with the database interface. The screen processor tells the ABAP processor which module of the screen flow logic should be processed next. The following screen illustrates the interaction between the screen and the ABAP processors when an application program is running.
Database Interface
The database interface provides the following services:
·        Establishing and terminating connections between the work process and the database.
·        Access to database tables
·        Access to Repository objects (ABAP programs, screens and so on)
·        Access to catalog information (ABAP Dictionary)
·        Controlling transactions (commit and rollback handling)
·        Table buffer administration on the ABAP application server.
The following diagram shows the individual components of the database interface:
The diagram shows that there are two different ways of accessing databases: Open SQL and Native SQL.
Open SQL statements are a subset of Standard SQL that is fully integrated in ABAP. They allow you to access data irrespective of the database system that your installation is using. Open SQL consists of the Data Manipulation Language (DML) part of Standard SQL; in other words, it allows you to read (SELECT) and change (INSERT, UPDATE, DELETE) data. The tasks of the Data Definition Language (DDL) and Data Control Language (DCL) parts of Standard SQL are performed in NetWeaver AS ABAP by the ABAP Dictionary and the authorization system. These provide a unified range of functions, irrespective of database, and also contain functions beyond those offered by the various database systems.
Open SQL also goes beyond Standard SQL to provide statements that, in conjunction with other ABAP constructions, can simplify or speed up database access. It also allows you to buffer certain tables on the ABAP application server, saving excessive database access. In this case, the database interface is responsible for comparing the buffer with the database. Buffers are partly stored in the working memory of the current work process, and partly in the shared memory for all work processes on an ABAP application server. Where NetWeaver AS ABAP is distributed across more than one ABAP application server, the data in the various buffers is synchronized at set intervals by the buffer management. When buffering the database, you must remember that data in the buffer is not always up to date. For this reason, you should only use the buffer for data which does not often change.
Native SQL is only loosely integrated into ABAP, and allows access to all of the functions contained in the programming interface of the respective database system. In Native SQL, you can primarily use database-specific SQL statements. The Native SQL interface sends them as is to the database system where they are executed. You can use the full SQL language scope of the respective database which makes all programs using Native SQL specific for the database system installed. In addition, there is a small set of SAP-specific Native SQL statements which are handled in a special way by the Native SQL interface. ABAP applications contain as little Native SQL as possible. In fact, it is only used in a few components (for example, to create or change table definitions in the ABAP Dictionary).
The database-dependent layer in the diagram serves to hide the differences between database systems from the rest of the database interface. You choose the appropriate layer when you install NetWeaver AS ABAP. Thanks to the standardization of SQL, the differences in the syntax of statements are very slight. However, the semantics and behavior of the statements have not been fully standardized, and the differences in these areas can be greater. When you use Native SQL, the function of the database-dependent layer is minimal.
Types of Work Process
Before you start NetWeaver AS ABAP, you determine how many work processes each ABAP application server will have, and what their types will be. Since all work processes have the same structure (see preceding section), the type of work process does not determine the technical attrributes of the ABAP application server but the type of tasks to be performed on it. The dispatcher starts the work processes and only assigns them tasks that correspond to their type. This means that you can distribute work process types to optimize the use of the resources on your ABAP application servers.
The following diagram shows again the structure of an ABAP application server, but this time, includes the various possible work process types:
Dialog Work Process
Dialog work processes deal with requests from an active user to execute dialog steps (see also Dialog Programming).
Update Work Process
Update work processes execute database update requests. Update requests are part of an SAP LUW that bundle the database operations resulting from the dialog in a database LUW for processing in the background.
Background Work Process
Background work processes process programs that can be executed without user interaction (background jobs).
Enqueue Work Process
The enqueue work process administers a lock table in the shared memory area. The lock table contains the logical database locks for NetWeaver AS ABAP and is an important part of the SAP LUW concept. In NW AS, you may only have one lock table. You may therefore also only have one ABAP application server with enqueue work processes. Normally, a single enqueue work process is sufficient to perform the required tasks.
Spool Work Process
The spool work process passes sequential datasets to a printer or to optical archiving. Each ABAP application server may contain only one spool work process.
Role of Work Processes
The types of its work processes determine the services that an ABAP application server offers. The application server may, of course, have more than one function. For example, it may be both a dialog server and the enqueue server, if it has several dialog work processes and an enqueue work process.
You can use the system administration functions to switch a work process between dialog and background modes while the system is still running. This allows you, for example, to switch an SAP System between day and night operation, where you have more dialog than background work processes during the day, and the other way around during the night.
thanks
karthik
reward me points if usefull

PDA and data synchronization -help required

Hi,
I have experince in developing web applications in jsp/servlets and php. I wish to develop a PDA supported java server
application. I have downloaded netbeans for using as an IDE. It does have support for mobile emulators, but does not support
PDA/Palm OS emulators.
What about IBM websphere and eclipse for using as IDE? Will they support J2ME SDK? Please help me in devoloping my PDA
application.
why we use data synchronisation for laptop and PDA for web applications? Why is it not applied in normal PC?
Thanking in advance,
From,
Vinod

Vinod, you might want to look at the palm.com web site. There is quite alot of information available for developers.
By reading your original query, I assume you are talking about thread safety and not synchronization, per se. Thread safety is very important in a web app as you surely know. If you don't and have been developing Servlets/JSPs then, hoo boy!

Authentication & Authorization with SSO, JAAS and Database Tables mix

Hi,
I'm looking for how manage Authentication & Authorization in a J2EE ADF+Struts+JSP application.
I'm interested in use SSO for authentication (I just did it programatically & dynamically already), and now I would like to could define authorization using database tables with users, groups, profiles, individual permissions, ..., (maitanined dynamically by web application admin) throught JAZN (JAAS or however is said) but not statically defining roles, groups, users, ... in jazn xml files.
I saw that exists the possibility to create a custom DataSourceUserManager class to manage all this, and this gave me the idea that this could be possible to do (I was thinking in make a custom Authorization API over my application tables, without JAZN) but what is better that use and extended and consolidated aprox like JAZN.
Anybody could tell me if my idea could be possible, and realizable, and maybe give me some orientation to build this approach.
A lot of thanks in advanced.
And sorry, excuse my so bad english.
See you.

Marcel,
Originally the idea was to create a post to only explain how to do authentication using a Servlet filter. However,
I have recently added code to the JHeadstart runtime and generators to enable both JAAS and 'Custom' authentication AND authorization in generated applications. Therefore, this post will be made after we have released the next patch release, as it will depend on these code changes.
We currently plan to have the patch release available sometime in the second half of May.
Kind regards,
Peter Ebell
JHeadstart Team

Reference and Assignment Synchronization Report for FBL5N Transaction

is ther any standard report for ...Reference and Assignment Synchronization Report for FBL5N Transaction.

Hi,
FBL5N is a standard TCode which is used to see Open, Cleared and All line items of customer as per company code.Line items means whatever transaction has been posted to the customer.
These line items may be related to invoices raised against the customer, payments received from customer and advance receipt from customer.
Hope you have understood
Regards
Tapan

Search static pages AND database tables

Hi,
I'm working on a project in which I have static content
pages, plus I'm creating a set of dynamic pages that display jobs
and events listings etc. The dynamic pages are going to run off an
access database.
I'm need to create a search facility on the site. At present
I'm planning to use a drop down box (or radio buttons ?) to allow
the user to select which part of the site to search (main site,
jobs or events), the selection will determine which search page the
form query is passed to (site text search or database query search
page).
Am I approaching this correctly.
Can anyone comment on possibly a better or alternative way of
providing such a search option ? (searching both static pages and
database tables)
Thanks in advance.

I guess something like <cffile action="read"
file="C:\docs\shopping.html" variable="shoppingList">. Is there
a way to do multiple files at once?

Workspace integration and Database Mapping

Hi there folks,
I have a couple of questions about Forte.
1 - When you integrate a workspace into the repository it takes all the
changes you have made in that workspace and 'saves' them to the
repository. However, what if you have a workspace which has a half
finished project as well as another project which you make a small but
important change to. The small change must go back because other
developers need the 'fix', but the half finished project will essentially be
'broken' if it is integrated at this stage. Is there any way to integrate
only specific projects? If not, how do you stop the half finished project
being copied into the other developers' workspaces when they do an
'Update'.
2 - We have designed a class called 'Criteria' which contains several
attributes, each of which are a class called 'Criterion'. The Criterion
class contains the attributes "Active", "From" and "To" which are simple
data types. Now if the 'Criteria' class is used for attributes in two other
classes (Say "ClassA" and "ClassB"), how can you match these
classes to RDBMS tables? I realise you could explicitly name columns
and attributes in SQL Select, Insert and Update statements, but that
has now defeated the purpose of creating the 'Criteria' class in the first
place. Namely, ease of future maintenance. Am I missing something
here?
Thanks in advance for any help.
Cheers,
Duncan Kinnear,
McCarthy and Associates, Email: [email protected]
PO Box 764, McLean Towers, Phone: +64 6 834 3360
Shakespeare Road, Napier, New Zealand. Fax: +64 6 834 3369
Providing Integrated Software to the Meat Processing Industry for over 10 years
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/>

Duncan,
1. There is no way to integrate a part of your workspace/class and not the other. So, before you integrate you have to make sure that it compiles and also your changes do not break what others are doing when they update. The only way to do it is to export the half finished projects/classes, integrate the good workspace and then import it back and continue your work.
It is important that there is some discipline and lot of unit testing as your application grows bigger and code larger and you go towards deployment. This will reduce the possibility of breaking others code (after you integrate and others update).
2. From what I have seen, compared to lot of tools Forte goes very far in providing a good and easy mapping from objects (rather object attributes) to table column mapping. All said and done there is a mismatch between pure objects and an RDBMS table. We have to live with it until we get to a stage where we can have OODBMSes which are still in its infancy compared RDBMSes. In forte you can map attributes of an object whose names are same as the column names. Another option is to alias the column names to match the attribute names in the SQL.
Now for my pet discussion of mapping objects to tables - It is easier and simple if you map an object to a table. OO purists might argue with me and say that is not very OOriented. That is right but we are dealing with a mismatch here. It is just that we are impedance matching by trying to persist an object into an RDBMS table.The other possibilities are to map 1 to many from object to a table and vice versa. Choose whatever is right for you. Eventually keep the performance in mind when you choose an approach.
Hope this helps.
Nirmal
Nirmal P Uppalapati Phone: (203) 622-5386
VP-US Operations (203) 359-3992
PSI Data Systems Ltd. Mobile: (203) 912-1302
Suite 406 Fax: (203) 359-4662
One Bank Street Email : [email protected]
Stamford, CT 06901 USA Web: http://www.psi.soft.net
-----Original Message-----
From: Duncan Kinnear [SMTP:[email protected]]
Sent: Wednesday, October 14, 1998 6:02 PM
To: [email protected]
Subject: Workspace integration and Database Mapping
Hi there folks,
I have a couple of questions about Forte.
1 - When you integrate a workspace into the repository it takes all the
changes you have made in that workspace and 'saves' them to the
repository. However, what if you have a workspace which has a half
finished project as well as another project which you make a small but
important change to. The small change must go back because other
developers need the 'fix', but the half finished project will essentially be
'broken' if it is integrated at this stage. Is there any way to integrate
only specific projects? If not, how do you stop the half finished project
being copied into the other developers' workspaces when they do an
'Update'.
2 - We have designed a class called 'Criteria' which contains several
attributes, each of which are a class called 'Criterion'. The Criterion
class contains the attributes "Active", "From" and "To" which are simple
data types. Now if the 'Criteria' class is used for attributes in two other
classes (Say "ClassA" and "ClassB"), how can you match these
classes to RDBMS tables? I realise you could explicitly name columns
and attributes in SQL Select, Insert and Update statements, but that
has now defeated the purpose of creating the 'Criteria' class in the first
place. Namely, ease of future maintenance. Am I missing something
here?
Thanks in advance for any help.
Cheers,
Duncan Kinnear,
McCarthy and Associates, Email: [email protected]
PO Box 764, McLean Towers, Phone: +64 6 834 3360
Shakespeare Road, Napier, New Zealand. Fax: +64 6 834 3369
Providing Integrated Software to the Meat Processing Industry for over 10 years
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/>
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/>

VALUE BASED PARTITIONING BETWEEN AN EXCEL AND DATABASE

Can any1 help I have an EXCEL FILES and DATABASE. I want to make partitioning value-based between these sources.
Thanks you in advances.

Hi,
Actually value based partitioning works fine on the data sources which are stored on RDBMS. I haven't try it with a excel source. There is a detailed description in the link below.
http://108obiee.blogspot.com/2009/01/fragmentation-in-obiee.html
Hope this helps,
Cheers.
Cuneyt

11gR2 RAC, ASM and database

Hi all,
I've installed 11gR2 RAC and database on Linux OEL 5.4. Everything seems Ok, I'm able to connect from client using SCAN, and load balancing works well, but "crs_stat -t" shows up some OFFLINE services, like gsd and oc4j.
Is this normal ? If yes, why it's so ? If not, what should I do to solve the problem ?
Thanks in advance.
Antoine

Thanks for your answer.
Those services are disabled, and I've found this one on MOS FAQs :
With Oracle Clusterware 11g Release 2, the GSD resource will be disabled by default. You only need to enable this resource if you are running Oracle 9i RAC in the cluster.

Oracle AQ, the Advanced Queueing Facility

Hi all,
Does someone have first hand experience using
Oracle AQ, the Advanced Queueing Facility?
I am primarily interested in understanding its reliability, usability and general industry acceptance.
thx
Kalpana Subramanian

DBMS_XMLQUERY and DBMS_XMLSAVE are implemented in Java. Neither are part of XQuery. However XQuery does require the java componant since the XQuery parser is currently written in Java. So while we can execute XQuery without Java we currently cannot parse XQuery statements without Java.
DBMS_XMLGEN and DBMS_XMLSTORE should be present in XE. They are almost 100% feature equivilant to XMLQUERY and XMLSAVE but are implemented in 'C' rather than java. For XML Generation (XMLQUERY/XMLGEN) you should also consider the SQL/XML operators (XMLElement, XMLAgg, XMLForest, XMLAttributes).

Advanced Queueing and databases synchronization

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