gpsaravanan202

 Profile Answers by gpsaravanan202 

• Dec 12th, 2007

 

The execution flow of sql statement is internally done by means of internal cursor.
these are steps followed in executing the statement
Parse
bind
execute
fetch
close cursor....
More details can be studied in oracle supplied packages concept...

ananth.dikshit

 Profile Answers by ananth.dikshit 

• Aug 27th, 2008

 

In Order to execute any SQL statement first we need to start an oracle instance. for that we need to connect to any tool(SQL* Plus) and that will start a user process. This user Process will contact the server on which oracle is installed and stats system process. system process will start the Oracle. One instance can be opened at a time for a database.
for example if I fire the below SQL statement
SQL> select count(*) from emp;

count
------
10

1 rows selected.

First it is Phrased. Meaning it will check for syntax and symantics in the query. and then it will choose an optimiser mode to execute the SQL. generally it is CHOOSE.  after selecting optimizer then it generate an explian plan. this explian plan is sent to execution engine to generate execution plan. SQL engine uses the generated execution plan and exeucutes the SQL.