What is sql?
Structured Query Language (SQL) is a language that provides an interface to relational database
systems. SQL w as developed by IBM in the 1970s for use in System R, and is a de facto standard, as w ell
as an ISO and ANSI standard. SQL is often pronounced SEQUEL.
In common usage SQL also encompasses
DM L (Data M anipulation Language), for INSERTs, UPDATEs, DELETEs and DDL (Data Definition
Language), used for creating and modifying tables and other database structures.
The development of SQL is governed by standards. A major revision to the SQL standard w as completed
in 1992, called SQL2. SQL3 support object extensions and are (partially?) implemented in Oracle8 and 9.
Sql interview questions:
1. Which is the subset of SQL commands used to manipulate Oracle Database structures, including
tables?
Data Definition Language (DDL)
2. What operator performs pattern mat ching?
LIKE operator
3. What operator tests column for the absence of data?
IS NULL operator
4. Which command executes the contents of a specified file?
START <filename> or @<filename>
5. What is the parameter substitution symbol used w ith INSERT INTO command?
&
6. Which command displays the SQL command in the SQL buffer, and then executes it?
RUN
7. What are the w ildcards used for pattern matching?
_ for single character substitution and % for multi-character substitution
8. State true or false. EXISTS, SOM E, ANY are operators in SQL.
True
9. State true or false. !=, <>, ^ = all denote the same operation.
True
10. What are the privileges that can be granted on a table by a user to others?
Insert, update, delete, select, references, index, execut e, alter, all
11. What command is used t o get back the privileges offered by the GRANT command?
REVOKE