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## org.apache.cayenne.dba.sybase
Class SybasePkGenerator

    java.lang.Object
      org.apache.cayenne.dba.JdbcPkGenerator
          org.apache.cayenne.dba.sybase.SybasePkGenerator

All Implemented Interfaces:
  PkGenerator

    public class SybasePkGenerator

extends JdbcPkGenerator

Primary key generator implementation for Sybase. Uses a lookup table named "AUTO_PK_SUPPORT" and a stored procedure "auto_pk_for_table" to search and increment primary keys for tables.

Author:
  Andrus Adamchik

Field Summary

Fields inherited from class org.apache.cayenne.dba.JdbcPkGenerator
`DEFAULT_PK_CACHE_SIZE, pkCache, pkCacheSize`

Constructor Summary
`SybasePkGenerator()`

Method Summary
`void` | `createAutoPk(DataNode node, List dbEntities)` Generates database objects to provide automatic primary key support.
`List` | `createAutoPkStatements(List dbEntities)` Returns a list of SQL strings needed to generates database objects to provide automatic primary support for the list of entities.
`void` | `dropAutoPk(DataNode node, List dbEntities)` Drops database objects related to automatic primary key support.
`List` | `dropAutoPkStatements(List dbEntities)` Returns SQL string needed to drop database objects associated with automatic primary key generation.
`protected int` | `pkFromDatabase(DataNode node, DbEntity ent)` Performs primary key generation ignoring cache.

Methods inherited from class org.apache.cayenne.dba.JdbcPkGenerator
`autoPkTableExists, binaryPK, dropAutoPkString, generatePkForDbEntity, getPkCacheSize, pkCreateString, pkDeleteString, pkSelectString, pkTableCreateString, pkUpdateString, reset, runUpdate, setPkCacheSize`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### SybasePkGenerator

    public SybasePkGenerator()

Method Detail

### createAutoPk

    public void createAutoPk(DataNode node,
                             List dbEntities)
                      throws Exception

  Generates database objects to provide automatic primary key support. Method will execute the following SQL statements:

  1. Executed only if a corresponding table does not exist in the database.

          CREATE TABLE AUTO_PK_SUPPORT (
             TABLE_NAME VARCHAR(32) NOT NULL,
             NEXT_ID INTEGER NOT NULL
          )

  2. Executed under any circumstances.

       if exists (SELECT * FROM sysobjects WHERE name = 'auto_pk_for_table')
       BEGIN
          DROP PROCEDURE auto_pk_for_table
       END

  3. Executed under any circumstances.

  CREATE PROCEDURE auto_pk_for_table @tname VARCHAR(32), @pkbatchsize INT AS BEGIN BEGIN TRANSACTION UPDATE AUTO_PK_SUPPORT set NEXT_ID = NEXT_ID + @pkbatchsize WHERE TABLE_NAME = @tname SELECT NEXT_ID from AUTO_PK_SUPPORT where NEXT_ID = @tname COMMIT END

  Specified by:
    `createAutoPk` in interface `PkGenerator`
  Overrides:
    `createAutoPk` in class `JdbcPkGenerator`
  Parameters:
    `node` - node that provides access to a DataSource.
    `dbEntities` - a list of entities that require primary key autogeneration support
  Throws:
    `Exception`

### createAutoPkStatements

    public List createAutoPkStatements(List dbEntities)

  Description copied from interface: `PkGenerator`
  Returns a list of SQL strings needed to generates database objects to provide automatic primary support for the list of entities. No actual database operations are performed.

  Specified by:
    `createAutoPkStatements` in interface `PkGenerator`
  Overrides:
    `createAutoPkStatements` in class `JdbcPkGenerator`

### dropAutoPk

    public void dropAutoPk(DataNode node,
                           List dbEntities)
                    throws Exception

  Drops database objects related to automatic primary key support. Method will execute the following SQL statements:

       if exists (SELECT * FROM sysobjects WHERE name = 'AUTO_PK_SUPPORT')
       BEGIN
          DROP TABLE AUTO_PK_SUPPORT
       END

       if exists (SELECT * FROM sysobjects WHERE name = 'auto_pk_for_table')
       BEGIN
          DROP PROCEDURE auto_pk_for_table
       END

  Specified by:
    `dropAutoPk` in interface `PkGenerator`
  Overrides:
    `dropAutoPk` in class `JdbcPkGenerator`
  Parameters:
    `node` - node that provides access to a DataSource.
    `dbEntities` - a list of entities whose primary key autogeneration support should be dropped.
  Throws:
    `Exception`

### dropAutoPkStatements

    public List dropAutoPkStatements(List dbEntities)

  Description copied from interface: `PkGenerator`
  Returns SQL string needed to drop database objects associated with automatic primary key generation. No actual database operations are performed.

  Specified by:
    `dropAutoPkStatements` in interface `PkGenerator`
  Overrides:
    `dropAutoPkStatements` in class `JdbcPkGenerator`

### pkFromDatabase

    protected int pkFromDatabase(DataNode node,
                                 DbEntity ent)
                          throws Exception

  Description copied from class: `JdbcPkGenerator`
  Performs primary key generation ignoring cache. Generates a range of primary keys as specified by "pkCacheSize" bean property.

  This method is called internally from "generatePkForDbEntity" and then generated range of key values is saved in cache for performance. Subclasses that implement different primary key generation solutions should override this method, not "generatePkForDbEntity".

  Overrides:
    `pkFromDatabase` in class `JdbcPkGenerator`
  Throws:
    `Exception`

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