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

Declaration

  define external db.set-transaction-type
      of value db.database database
      to value integer    mode

Argument definitions

database

is a db.database object obtained by opening a connection to a database using one of the dbOpen functions.

mode

is the desired transaction mode, either auto commit or manual commit.

Use db.set-transaction-type to set the mode of a database connection to either auto-commit or manual-commit.

Requirements

The db.database object database must be:

• open (else external exception OMDB101)
• in scope (else external exception OMDB103)

The value for mode may be either

• db.auto-commit - All transactions are committed as soon as they are performed.
• db.manual-commit - No transactions are commmitted to the database until the user calls the db.commit function.

Usage Notes

The default mode is auto-commit. In this mode, every insert, delete, or update operation is a permanent change to the database. In manual-commit mode, however, these operations are not permanent until they are committed using dbCommit. In manual-commit mode, operations can be rolled back (canceled) with dbRollback.

Example

The following example shows a simple transaction comprising two database insertions:

  import "omdb.xmd" prefixed by db.
  process
     local db.database this-db
     local db.table course
     local db.table schedule

     local stream course-data variable initial
     {   '504' with key 'cid',
         'What is that Sound?' with key 'CourseName'
     }

     local stream schedule-data variable initial
     {   '504' with key 'cid',
         '2000/03/21' with key 'CourseDate'
     }

     ;  create the database OMX objects
     set this-db to db.open-odbc 'dbDemo'
     set course to db.open-table in this-db table 'Course'
     set schedule to db.open-table in this-db named 'Schedule'

     ; start a transaction
     db.set-transaction-type of this-db to db.manual-commit

     ; add records to the two tables
     db.insert into course from course-data
     db.insert into schedule from schedule-data

     ; commit the transaction
     db.commit this-db

     ; 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'

         ; if the transaction was not finished,
         ; we must roll it back in the catch
         db.rollback this-db

Related Syntax    db.execute-in    db.database    db.insert    db.update    db.delete    db.table    db.commit    db.rollback    dbStatementExecute

Related Concepts    Using the OMDB library

Other Library Functions    db.advance-recordset    db.close    db.commit    db.compile-statement    db.database    db.delete    db.discard    db.execute    db.execute-in    db.field    db.insert    db.move-record    db.omdb-version    db.omdb-version-oci8    db.omdb-version-oci8i    db.omdb-version-odbc    db.open-oci8    db.open-oci8i    db.open-odbc    db.open-procedure    db.open-table    db.prepare    db.procedure    db.query    db.reader    db.record-exists    db.rollback    db.set-transaction-type    db.statement    db.streaming-execute    db.table    db.update    db.writer

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