What does operation column in plan table do?

What does operation column 开发者_如何转开发in plan table do?? I am working on Oracle 10g and I would like to know about the significance of values in that particular column!

From the same Oracle 10G Performance Tuning Guide I linked to in a previous question:

Name of the internal operation performed in this step. In the first row generated for a statement, the column contains one of the following values:

• DELETE STATEMENT
• INSERT STATEMENT
• SELECT STATEMENT
• UPDATE STATEMENT

See Table 19-3 for more information on values for this column.

I found this by looking in the index under "O" for "Operation".

The operation column tells you what kind of operation is being performed here. It can take values like INSERT STATEMENT, HASH JOIN, TABLE ACCESS, or SORT.