What are the various types of queries ?

The types of queries are:

  1. Normal Queries
  2. Sub Queries
  3. Co-related queries
  4. Nested queries
  5. Compound queries

What is a transaction ?

A transaction is a set of SQL statements between any two COMMIT and ROLLBACK statements.

What is PL/SQL?

PL/SQL is Oracle's Procedural Language extension to SQL.The language includes object oriented programming techniques such as encapsulation, function overloading, information hiding (all but inheritance), and so, brings state-of-the-art programming to the Oracle database server and a variety of Oracle tools.

Is there a PL/SQL Engine in SQL*Plus?

No.Unlike Oracle Forms, SQL*Plus does not have a PL/SQL engine.Thus, all your PL/SQL are send directly to the database engine for execution.This makes it much more efficient as SQL statements are not stripped off and send to the database individually.

Is there a limit on the size of a PL/SQL block?

Currently, the maximum parsed/compiled size of a PL/SQL block is 64K and the maximum code size is 100K.You can run the following select statement to query the size of an existing package or procedure. SQL> select * from dba_object_size where name = 'procedure_name'