XDFLD segment type format

The IMS catalog XDFLD segment type contains metadata about an indexed field in a secondary index relationship.

Each XDFLD segment instance is a direct child of an LCHILD segment instance that defines a secondary index relationship.
Segment name
XDFLD
Parent name
LCHILD
Sequence field
XDFLDSEQ
Segment length
618 bytes
Table 1. XDFLD segment type format
Offset (bytes) Length (bytes) Data type Field name Description Unique key field
1 2 X LEN Length of this segment.  
3 2 C CTL Control field.  
5 2 X XDFLDSEQ Sequence field, type = U. X
5 2 X SEQNUM Sequence number.  
9 8 C IMSNAME Name of this segment.  
17 8 C SEGMENT Indicates the name of the index source segment type for the secondary index relationship.  
25 8 C SRCH1 This field is no longer maintained. Refer to the row for the XSRCH1 field in this table.  
33 8 C SRCH2 This field is no longer maintained. Refer to the row for the XSRCH2 field in this table.  
41 8 C SRCH3 This field is no longer maintained. Refer to the row for the XSRCH3 field in this table.  
49 8 C SRCH4 This field is no longer maintained. Refer to the row for the XSRCH4 field in this table.  
57 8 C SRCH5 This field is no longer maintained. Refer to the row for the XSRCH5 field in this table.  
65 8 C SUBSEQ1 This field is no longer maintained. Refer to the row for the XSUBSEQ1 field in this table.  
73 8 C SUBSEQ2 This field is no longer maintained. Refer to the row for the XSUBSEQ2 field in this table.  
81 8 C SUBSEQ3 This field is no longer maintained. Refer to the row for the XSUBSEQ3 field in this table.  
89 8 C SUBSEQ4 This field is no longer maintained. Refer to the row for the XSUBSEQ4 field in this table.  
97 8 C SUBSEQ5 This field is no longer maintained. Refer to the row for the XSUBSEQ5 field in this table.  
105 8 C DDATA1 Indicates one of up to five fields in the index source segment that are used as the duplicate data field of the secondary index.  
113 8 C DDATA2 Indicates one of up to five fields in the index source segment that are used as the duplicate data field of the secondary index.  
121 8 C DDATA3 Indicates one of up to five fields in the index source segment that are used as the duplicate data field of the secondary index.  
129 8 C DDATA4 Indicates one of up to five fields in the index source segment that are used as the duplicate data field of the secondary index.  
137 8 C DDATA5 Indicates one of up to five fields in the index source segment that are used as the duplicate data field of the secondary index.  
145 8 C EXITRTN The name of the user-supplied Secondary Index Database Maintenance exit routine for this secondary index relationship.  
153 8 C PSELRTN The name of the user-supplied Partition Selection exit routine that is used when user partitioning is requested for this HISAM or SHISAM database that is defined as secondary index for a Fast Path primary database.  
161 1 C PSELOPT Indicates how partition databases in a user partition group are logically grouped for GN calls that can process past the end of the first partition:
M (multiple grouping)
The selected user partition and subsequent partitioned databases are included in the group as they are defined in the NAME field of the LCHILD segment instance in the primary DEDB catalog record.
S (single grouping)
Only the selected user partition database is used.
 
162 3 C FILLER01 Reserved.  
165 5 C CONSTANT Indicates a character that identifies every index pointer in a particular secondary index. This value differentiates pointers for different secondary indexes that are stored in the same database.  
170 5 X NULLVAL The pointer suppression value for index search fields. No index pointers are created when all of the SRCH fields of the index source segment contain this value.  
175 26 C NAME Indicates the name of the data field of an index target segment.  
201 13 C XSRCH1 Indicates one of up to five fields in the index source segment that are used as search fields in the secondary index.  
214 13 C XSRCH2 Indicates one of up to five fields in the index source segment that are used as search fields in the secondary index.  
227 13 C XSRCH3 Indicates one of up to five fields in the index source segment that are used as search fields in the secondary index.  
240 13 C XSRCH4 Indicates one of up to five fields in the index source segment that are used as search fields in the secondary index.  
253 13 C XSRCH5 Indicates one of up to five fields in the index source segment that are used as search fields in the secondary index.  
266 13 C XSUBSEQ1 Indicates one of up to five fields in the index source segment that can be used as subsequence fields in the secondary index.  
279 13 C XSUBSEQ2 Indicates one of up to five fields in the index source segment that can be used as subsequence fields in the secondary index.  
292 13 C XSUBSEQ3 Indicates one of up to five fields in the index source segment that can be used as subsequence fields in the secondary index.  
305 13 C XSUBSEQ4 Indicates one of up to five fields in the index source segment that can be used as subsequence fields in the secondary index.  
318 13 C XSUBSEQ5 Indicates one of up to five fields in the index source segment that can be used as subsequence fields in the secondary index.  
331 32 C FILLER02 Reserved.  
363 256 C XDFLDUSERDATA Indicates the user data of the user-supplied Secondary Index Database Maintenance exit routine.