ELIMINAR Y/O EVITAR FORMACIÓN DE BIOFILMS

A HDAM or HIDAM database may be migrated to HALDB with the following steps:

򐂰 Unload of the existing database using HD Unload and specifying MIGRATE=YES

򐂰 DBDGEN as a HALDB database

򐂰 Deletion of database information from the RECONs

򐂰 Definition of the partitions

򐂰 Allocation of database data sets

򐂰 Partition initialization

򐂰 Reload as a HALDB database using HD Reload

򐂰 Image copy of the database data sets

Secondary indexes are created when their indexed database is migrated. They are created with the following steps:

򐂰 DBDGEN as a HALDB secondary index

򐂰 Deletion of secondary index database information from the RECONs

򐂰 Definition of partitions

򐂰 Allocation of database data sets

򐂰 Sort of output file from the unload of the indexed database

򐂰 Load of the secondary index using HD Reload

򐂰 Image copy of the database data sets

The migration of databases without logical relationships or secondary indexes is explained in 8.3, “Migrating simple databases” on page 96.

Changed and additional steps for the migration of databases with secondary indexes are explained in 8.5, “Migrating databases with secondary indexes” on page 101.

If databases are logically related, they must be migrated together. Changed steps for the migration of these databases are explained in 8.6, “Migrating databases with logical relationships” on page 114.

8.1.1 DBD changes

You must modify the DBD for any database that you migrate to HALDB. This section explains the modifications that are required.

HIDAM index DBDs

There is no DBD for a PHIDAM primary index. When a HIDAM database is migrated to PHIDAM, the DBD for the HIDAM Index is discarded. IMS gets the information required to generate the PHIDAM primary index from the PHIDAM DBD.

DBD statement

There are the following three changes to the DBD statement for HALDB:

򐂰 There are new values for the ACCESS parameter. They are PHDAM, PHIDAM, and PSINDEX. The value should be changed to the appropriate value.

򐂰 The optional PSNAME parameter has been added. It is used to specify a default partition selection exit routine. If you are not going to use the exit routine, do not specify this parameter.

򐂰 The RMNAME parameter has a slightly different meaning. With PHDAM databases it is optional. It is used to define default randomizer values for partitions. These values may be changed for individual partitions when they are defined.

DATASET statement

The DATASET statement is not used in HALDB DBDs. The entities it defines for non-HALDB databases are handled differently with HALDB as follows:

򐂰 DDNAMEs are created by the definition of partitions.

򐂰 Data set groups are defined by the DSGROUP parameter on SEGM statements.

򐂰 Free space and OSAM block size specifications are made when partitions are defined.

򐂰 The SCAN parameter is not specified with HALDB DBDs. HALDB operates as if SCAN=0 were specified. This is also the recommended value for

non-HALDB databases.

SEGM statement

There are the following three changes to the SEGM statement for HALDB:

򐂰 The valid specifications for the PTR parameter have changed.

HALDB does not use hierarchic pointers. Any use of HIER, H, HIERBWD, or HB keywords with the PTR parameter must be changed to TWIN, T,

TWINBWD, or TB.

PHIDAM does not support the use of twin forward only (TWIN or T) pointers for root segments. If you have HIDAM roots using twin forward only pointers,

the keyword for the PTR parameter on the SEGM statement should be changed to NOTWIN, NT, TWINBWD, or TB.

HALDB does not use symbolic pointers. Changes required for logical relationships are explained in “Changing pointer options for logical relationships” on page 115.

򐂰 The specification of data set groups for HALDBs is done with the DSGROUP parameter.

You may not want to maintain multiple data set groups. If you do want multiple data set groups, you must specify the DSGROUP parameter on the SEGM statement for any segment that is not in the first data set group. The valid values for DSGROUP are the letters A through J. A is the first data set group, B is the second, and J is the tenth.

򐂰 The BYTES parameter for a secondary index segment must be increased by four bytes if a /SX field is used as a subsequence field. We explain this further in “/SX subsequence fields” on page 102.

LCHILD statement

The LCHILD statement is not used to define the primary index in a HIDAM DBD. When converting a HIDAM DBD to PHIDAM, this LCHILD statement should be deleted.

When converting a secondary index DBD to a HALDB PSINDEX DBD, there are three possible changes required:

򐂰 If PTR=SYMB is specified in a secondary index, it must be changed to PTR=SNGL or omitted. PTR=SNGL is the default and only valid specification for PSINDEX LCHILD statements.

򐂰 If PTR=SYMB is specified in a HDAM or HIDAM indexed database, it must be changed to PTR=INDX.

򐂰 An RKSIZE parameter must be specified on the LCHILD statement in the secondary index DBD. This is the size of the root’s key in the target database. When converting a logical relationship using symbolic pointing, you must omit the PTR=SYMB specification on the LCHILD statement for the logical relationship. The changes for LCHILD statements used to define logical relationships using virtual pairing are explained in “Making changes to the DBDs for physical pairing” on page 116.

XDFLD statement

HALDB does not support shared secondary indexes. If the CONST parameter is specified in an XDFLD statement of an indexed database, it must be deleted. The

CONST parameter is used to specify the character associated with a shared secondary index. Each HALDB secondary index must be stored in its own secondary index database. Separate PSINDEX databases must be defined for each shared secondary index being converted to HALDB.

FIELD statement

The BYTES parameter of the sequence field for a secondary index segment must be increased by four bytes if a /SX field is used as a subsequence field. We explain this further in “/SX subsequence fields” on page 102.