org.apache.cayenne.dba.sybase
Class SybasePkGenerator

java.lang.Object
  extended by org.apache.cayenne.dba.JdbcPkGenerator
      extended by 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:
Andrei Adamchik

Field Summary
 
Fields inherited from class org.apache.cayenne.dba.JdbcPkGenerator
DEFAULT_PK_CACHE_SIZE, NEXT_ID, objDesc, pkCache, pkCacheSize, resultDesc
 
Constructor Summary
SybasePkGenerator()
           
 
Method Summary
 void createAutoPk(DataNode node, java.util.List dbEntities)
          Generates database objects to provide automatic primary key support.
 java.util.List createAutoPkStatements(java.util.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, java.util.List dbEntities)
          Drops database objects related to automatic primary key support.
 java.util.List dropAutoPkStatements(java.util.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, generatePkForDbEntityString, 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,
                         java.util.List dbEntities)
                  throws java.lang.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:
java.lang.Exception

createAutoPkStatements

public java.util.List createAutoPkStatements(java.util.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,
                       java.util.List dbEntities)
                throws java.lang.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:
java.lang.Exception

dropAutoPkStatements

public java.util.List dropAutoPkStatements(java.util.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 java.lang.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:
java.lang.Exception


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