Rows of constants

The insert cursor mechanism supports one special case where high performance is easy to obtain. In this case, all the values listed in the INSERT statement are constants: no expressions and no host variables are listed, just literal numbers and strings of characters. No matter how many times such an INSERT operation occurs, the rows it produces are identical. When the rows are identical, copying, buffering, and transmitting each identical row is pointless.

Instead, for this kind of INSERT operation, the PUT statement does nothing except to increment a counter. When a FLUSH operation is finally performed, a single copy of the row and the count of inserts are passed to the database server. The database server creates and inserts that many rows in one operation.

You do not usually insert a quantity of identical rows. You can insert identical rows when you first establish a database to populate a large table with null data.