Grouping to form a record type Schema DDL
68 U929-J-Z125-9-76
4.5 Grouping record elements to form a record type RECORD NAME IS record-name
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⎧ ⎧PICTURE.....⎫ ⎫
⎨[level-number ]record-element-name[ ⎨ ⎬][ OCCURS.....].⎬...
⎩ ⎩TYPE.. ... ⎭ ⎭
A record type is a named collection of record elements. A recor d element may be an item,
a vector or a repeating group.
A single occurrence of a record type is a record. A record thus c onsists of one item content
each of all the items represented in the record type.
A record type is also the smallest unit of data recognized by UDS/SQL by means of a unique
identifier - the database key. All record elements therefore have to be defined as parts of
record types.
record-name specifies the name of the record type assigned by the user.
record-element-name specifies the record element which is to become part of the record type.
It must be defined as described on page 55 through page 6 5.
The total length of all record elements within a record type must not exceed the maximum
record length.
Depending on which page length was defined for the database, the maximum record len gth
may be:
– 2020 bytes for a 2048-byte page length (2-Kbyte page format)
– 3968 bytes for a 4000-byte page length (4-Kbyte page format)
– 8064 bytes for a 8096-byte page length (8-Kbyte page format)
The maximum record length could, however, also be somewhat lower, depending on the
connection data for the record (see “SCD” on page 219).
The following applies to the maximum number of record types per da tabase:
– A maximum of 253 record types can be defined in the schema of a database with a page
length of 2048 bytes.
– A maximum of 32 766 record types can be defined in the schema of a database with a
page length of 4000 or 8096 bytes.