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RDB/VMS Relational Database Operator ERASE — VMS CDD+_4.1A

 Erases records from a relation.  Before using the ERASE statement,
 you must start a READ_WRITE transaction and establish a record stream
 using a context variable with a FOR statement or a START_STREAM
 statement.  You cannot erase records from a view that was formed with
 a WITH, REDUCED, or CROSS clause.

 Example:

     RDO> START_TRANSACTION READ_WRITE RESERVING
     cont>  COLLEGES FOR EXCLUSIVE WRITE
     RDO>     FOR C IN COLLEGES
     cont>      ERASE C
     cont>    END_FOR
     RDO> COMMIT

Additional information available:

FormatExamples

Format

 ERASE ────> context-var ───┬────────>───────┬──>
                            └──> on-error ───┘

 context-var  A temporary name specified in an RSE for name
              recognition.  You must define the context variable in a
              START_STREAM statement or in a FOR loop.  Request HELP
              on RSE for more information.

 on-error     The ON ERROR clause, which specifies a host language
              statement or Rdb/VMS data manipulation statement to be
              performed if an Rdb/VMS error occurs.  Request HELP on
              ON_ERROR for more information.

Examples

 Example 1

 Assume you wish to erase all the records in the COLLEGES relation:

 RDO> START_TRANSACTION READ_WRITE RESERVING
 cont>  COLLEGES FOR EXCLUSIVE WRITE
 RDO> FOR C IN COLLEGES ERASE C END-FOR
 RDO> PRINT COUNT OF C IN COLLEGES
  0
 RDO> COMMIT

 This statement uses the loop established by the FOR statement and
 erases all the records from the COLLEGES relation.

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