Difference between driving table and driver table in Oracle
I need to know the difference between the driving table and driver table in Oracle.
I need to know the difference between the driving table and driver table in Oracle. Also while writing the query which table should come fist and which one should come second in the from clause? Please explain with example.
When you perform a join of two tables, one table is the "driving table." The driving table is the one that Oracle processes first in the join. Oracle reads a record in the driving table and then tries to find matching records (determined by the join condition) in the other table.
In older versions of Oracle (pre-9i), the driving table was the first table in the FROM clause. You could also specify the driving table with the use of optimizer hints. In Oracle 9i and 10g, the Cost-Based Optimizer chooses the driving table. The order in the FROM clause is not necessarily used to determine the driving table with the newer CBO.
