Secondary index database list

The following figure provides a list of the secondary indexes that you can use to access the database you specified on the Data Base Specification screen or selected from the Member List screen. The Secondary Index Data Base List screen is displayed only if Y is specified in the Use Secondary Indexing field and the primary DBD has two or more secondary indexes.

Secondary Index Data Base List

The order of the secondary indexes listed is based on the order of the secondary indexes defined in the physical DBD.

Line Cmd

Enter S to select the secondary index.

Index DBD

The secondary index DBD name.

Target Segment

The segment that resides in the primary database and is pointed to by the secondary index’s pointer segment.

Source Segment

The segment that resides in the primary database and contains the source fields used to retrieve the target segment.

Source Field(s)

Displays a list of up to five fields defined in the source segment that are used as the key to retrieve the target segment. The source fields are listed in the sequence of concatenation for the target segment’s key.

Selecting a Secondary Index

You can select a secondary index DBD from the list in one of the following ways:

• Move the cursor down the left side of the screen and enter S in front of a secondary index DBD.
• Enter the SELECT primary command in the Command field.

Terminating the Screen

Do one of the following to terminate the Secondary Index Data Base List screen:

• Press Enter. If you entered Y in the Exclude Segments field on the Data Base Specification screen, the Exclude Segment Specification screen is displayed. Otherwise, based on the region type specified, the Data Base Dataset Specification screen or the appropriate Region Type Specification screen is displayed.
• Enter END if you want to terminate the Secondary Index DBD List screen. The Data Base Specification screen is displayed
• Enter the RETURN command to return directly to the Primary Option Menu.

Because no segments were excluded in the PORDR example and the region type was DL/I, the next screen displayed is the Data Base Dataset Specification screen.

Static PSB

The Following figure shown, displays the Data Base Specification Screen for Static PSB.

If your IMS environment definition includes support for IMS Managed ACB, the Data Base Specification Screen displays as shown in Data Base Extract - Data Base Specification Screen (IMS Managed Database).

If your IMS environment definition includes support for COPE Managed Databases, the Data Base Specification Screen displays as shown in Data Base Extract - Data Base Specification Screen (COPE Managed Databases).

Data Base Extract - Data Base Specification Screen (Static PSB)

Extract Job Type

Enter one of the following:

PSBLIB dataset 1 and dataset 2

Enter one or two PSB library data set names.

When you enter two PSB libraries, File-AID for IMS searches the first before the second to locate the PSB member.

Member

Enter the name of the PSB to be used for the extract.

This PSB must contain all the PCBs with the correct processing options required to perform the extract. See PCBs Used for Extract for more information about PCBs required to perform an extract. Leave the member blank to select the PSB from the list of PSBs.

DBDLIB dataset 1 and dataset 2

Enter one or two DBD load library data set names that contain the DBD describing the database that you want to extract from (i.e., the "FROM" data base.

When you enter two DBD libraries, File-AID for IMS searches the first before the second to find the DBD entered.

Member

Enter the member that describes the database from which you want to extract (that is, the FROM database). The DBD member entered must describe a physical database. Logical and index DBDs are not supported. Leave the member blank to select the DBD from the list of PCBs in the static PSB.

Secondary indexing

If a secondary index is used, a key file of secondary index key values may be used with or without additional selection criteria, or selection criteria may be defined on secondary index key fields.

When a secondary index is used to drive extract processing, the index value is used to retrieve the segment defined as the target of the index. The database ROOT segment is retrieved and used to extract the database record just as if the ROOT key had been used from the start.

Extract Based on Key Values

Defines whether an external data set containing database key values will be used to drive the extract. These key values may be ROOT keys, fully qualified concatenated keys or if you have chosen to use a secondary index to drive extract processing, the data set may contain secondary index values.

Enter one of the following:

Keys dataset

Specify the keys data set that contains the key values for extract.

Member

Specify the member in the keys data set that contains the key values for the extract.

If you choose to use an external data set to drive extract processing, INPUT statements may be specified using formatted or unformatted selection criteria to indicate the locations in the data set that are to be used to construct key values. This option is available when specifying ROOT key or secondary index values. It is not possible to use INPUT statements to define locations to be used to construct fully qualified concatenated key values.

If INPUT statements are not specified in selection criteria, it is assumed that the key values are found starting in position 10 for a length equal to that of the key to be used. The key values must be entered exactly as they are stored on the target database. For example, packed numeric data must be entered as packed numeric data.

If fully qualified concatenated keys are to be used, the name of the IMS segment to be extracted must be entered on each record in positions 1 through 8. The name must be left justified.

When a fully qualified concatenated key is used to drive extract processing, by default, each segment associated with the key value is extracted along with its children. In addition, each parent segment along the path from the ROOT segment to the target segment are extracted. This produces an extract data set that can be loaded using a load procopt.

You may use selection criteria to restrict the segments that will be extracted. If you use selection criteria in this manner, For more information, see Key Value With Both INPUT And Selection Value.

The following table describes the default layout for key values appearing in a keys library member. If the layout of the keys does not correspond to that shown in the following table, then Option 6, Selection Criteria must be used to define the layout. Details concerning this procedure are found in sections Formatted Criteria Screen and Unformatted Criteria Screen in this space. The Formatted Criteria Screen applies when using formatted selection criteria. The Unformatted Criteria Screen applies when using unformatted selection criteria.

Default Key File Layout