Library: Database access (OMDB) Import: omdb.xmd

Declaration

define external function db.delete
 from  value    db.table  table
 where value    stream   condition

Argument definitions

table

is an open db.table object.

condition

is a condition to limit the number of rows deleted.

Use db.delete to delete records from a table using the supplied criteria.

Requirements

The condition must be

• valid SQL (else external exception OMDB501) or
• the specially defined constant db.all-records-match (all records in the table will be removed).

Usage Notes

None.

Example

The following example uses db.delete to remove grade references for students who did not finish a course. The deletion is performed through the db.table OMX component.

  import "omdb.xmd" prefixed by db.
  
  process
      local db.database this-db
      local db.table student-course
  
      ;  create the database OMX objects
      set this-db to db.open-odbc 'dbDemo'
      set student-course to db.open-table in this-db named 'StudentCourse'
  
      ;  drop students who did not finish from course lists
      db.delete from student-course where "Grade is NULL"
  
      ;  catch the database exceptions
      catch #external-exception identity catch-id message catch-msg
          output 'An error occurred while accessing an OMDB function.%n'
          output '%g(catch-id)  :  %g(catch-msg)%n'

Related Syntax db.database db.open-table dbTableClose db.insert db.update db.table db.commit db.set-transaction-type db.rollback

Related Concepts Using the OMDB library

Other Library Functions

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