Updating multiple rows in pl sql
This article introduces the new MERGE SQL command (sometimes referred to as "UPSERT").
MERGE is a DML command that enables us to optionally update or insert data into a target table, depending on whether matching records already exist.
It is created on a SELECT Statement which returns more than one row. General Syntax for creating a cursor is as given below: In the above example we are creating a cursor ‘emp_cur’ on a query which returns the records of all the employees with salary greater than 5000. When the data is fetched it is copied to the record or variables and the logical pointer moves to the next row and it becomes the current row.
Here ‘emp_tbl’ in the table which contains records of all the employees. On every fetch statement, the pointer moves to the next row.
This demonstrated the (then new) bulk PL/SQL processing enhancements introduced in Oracle 8i.
There were workarounds available to overcome this limitation, but they often performed less well.
Oracle 9i Release Two introduces BULK COLLECT support for collections of records.
works fine when I try to update all the records in tbl A, however, in this case I only have missing data which I have identified and populated in tbl B.
When I try to update only the missing data the non-matched data is also updated but to NULL. The reason some of your rows are getting NULLs updated is due to the subquery.This article shares what we’ve learned about ways to write PL/SQL in the Oracle Application Express environment.