|
01 Overview
SQL
-
Structured Query
LANGUAGE
Standard
LANGUAGE
BETWEEN
most databse applications (although Microsoft has added
it
's own proprietary statements)
IN
general,
SQL
IS
a way
TO
select certain records from database tables,
USING
criteria you choose.
SQL
consists
OF
creating a query
-
a string
-
that the database server interprets
WITH
SQL
you can:
-
Modify a database
's structure (create tables)
-
Change system security settings
-
ADD
USER
permissions
ON
databases
OR
tables
-
Query a database
FOR
information
-
UPDATE
the contents
OF
a database (
ADD
/
DELETE
DATA
)
-
Store your queries within your program
OR
database.
A database server application receives the query
AND
returns information (usually
databse records according
TO
the instructions
IN
the query
Example
OF
SQL
query (string):
SELECT
*
FROM employee
*
means
ALL
records
employee
IS
the
TABLE
OF
employees
Commonly available applications which support
SQL
include: Microsoft Access, Oracle, Microsoft Query
|