Sql Processing Steps

 

 

Whenever you issue a sequel statement it goes through a series of steps.

  • Syntax check - grammer mistake
  • Semantic check - Sees whether Sql statement is valid. That means whatever the tables the user is refereeing are already there in the database.
  • Shared pool Check - if the same kind of Sql has been executed before then it finds that particular Sql when and it directly executes the statement.
  • Optimization (Generation of multiple execution plans) - Let Suppose if it didn't find a similar sequence statement in shred prool, then it goes to fourth phase Optimization, where statement is generation of multiple execution plans.
  • Rows / Data Generation - on basis of best execution plan SQL shows the result set. 

 


Related Question