ABAP Data Base Updates Complete

You can update databases either using ABAP's Open SQL commands, or with the database-specific commands of your database's Native SQL command set.You can access ABAP cluster databases using special ABAP commands.

You can access the data in database tables using the Open SQL commands. The command set includes operations of the Data Manipulation Language (DML). The Data Definition Language (DDL) operations are not available in Open SQL, as these functions are performed by the ABAP Dictionary.Native SQL commands allow you to carry out both DML and DDL operations.The commands for ABAP cluster databases enable operations to be carried out on the data in the cluster databases. The tables themselves are created in the ABAP Dictionary as transparent tables.

Each time you access the database using Open SQL, the database interface of each work process (application server) converts this to a database-specific command. For this reason, the ABAP programs themselves are independent of the database used and can be transferred to other system platforms (with a different database system) without additional programming requirements.SAP database tables can be buffered at the application server level. The aims of buffering are to.Reduce the time needed to access data with read accesses. Data on the application server can be accessed more quickly than data on the database.Reduce the load on the database. Reading the data from application server buffers reduces the number of database accesses.The buffered tables are accessed exclusively via database interface mechanisms.

Database accesses with Native SQL enable database-specific commands to be used. This requires a detailed knowledge of the syntax in question. Programs that use Native SQL commands need additional programming after they are transported to different system environments (different database systems), since the syntax of the SQL commands generally varies from one database to the next.The target quantity can be limited on the database using all the Open SQL commands discussed here.One or more rows can be processed with a SQL command. Each command also provides the option of specifying the table name dynamically.In addition to this, each type of operation has a syntax variant, which can be used to change individual fields in a row.

With masked field selections (WHERE LIKE ''), note that '_' masks an individual character and '%' masks a character string of any length (in line with the SQL standard).For all Open SQL commands, you can edit data in the current client (standard). To do so, you do not specify any command additions and leave the client field non valuated.If you want to edit data from other clients explicitly, use the SQL command with the addition CLIENT SPECIFIED and enter the number of the client in which the SQL operation is to be carried out in the WHERE clause of the command.

All Open SQL commands return confirmation of the success or failure of the database operation in the form of a return code. This is always returned by the database interface in the sy-subrc system field. The return code '0' (zero) always means that the operation has been completed successfully. All other values mean that errors have occurred. For further details, please refer to the keyword documentation for the command in question.

In addition, the sy-dbcnt system field displays the number of records for which the desired database operation was actually carried out.Note that Open SQL commands do not perform any automatic authorization checks. You need to carry these out separately (see unit Authorization Checks).To insert a new row in a database table, enter the command INSERT INTO VALUES . To do so, you must specify the data to be written to the database in the structure (key and non-key fields) before the command.
If you receive a return code other than zero from the database interface in response to an Open SQL statement for changing data in the database, you should make sure that the database is reset to the status it had before the change attempt was made. You can do this by means of a database rollback.
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