The Essential Guide to Oracle INSERT INTO SELECT Statement.
Oracle Engine uses a work area for its internal processing to execute SQL statements. This work area is private to SQL's operations and is called a cursor.; The data stored in the cursor is called the active data set.; Cursor contains information on a SELECT statement and the rows of data accessed by it.
In the following example, two employee rows are added using two separate INSERT statements, and then both rows are updated using a single UPDATE statement. The JOBHIST table shows the action of the trigger for each affected row: two new hire entries for the two new employees and two changed commission records. The EMPCHGLOG table also shows that the trigger was fired a total of four times.
Problem. In a typical data warehousing application, quite often during the ETL cycle you need to perform INSERT, UPDATE and DELETE operations on a target table by matching the records from the source table. For example, a products dimension table has information about the products and you need to sync-up this table with the latest information about the products from the source table.
You can use the RETURNING BULK COLLECT INTO clause with the EXECUTE IMMEDIATE statement to store the results of an INSERT, UPDATE, or DELETE statement in a set of collections. Only INSERT, UPDATE, and DELETE statements can have output bind variables. You bulk-bind them with the RETURNING BULK COLLECT INTO clause of EXECUTE IMMEDIATE.
Have a larger blocksize - The time delay in an Oracle delete is largely the time spent writing the new blocks to disk, and placing the table into a 32k blocksize will marginally speed-up delete DML because there will be more rows deleted before a physical write. This speed difference can range from zero up to ten percent, depending on the type of delete and the sequencing of the rows.
These basic operations are INSERT, SELECT, UPDATE and DELETE statements in SQL language. Although the target database system is Oracle Database, but the same techniques can be applied to other database systems as well because of the query syntax used is standard SQL is generally supported by all relational database systems.
SELECT into ROWTYPE: 22.10.11. SELECT into TYPE: 22.10.12. Multiple-row SELECT command. 22.10.13. Multiple-row SELECT command with several exception-handling routines: 22.10.14. Create a loop that prints a list of all employees and their managers: 22.10.15. You must have the same datatypes in both the SELECT and INTO clauses. 22.10.16.