A database most often contains one or more tables. Each table is identified by a name (e.g. "Customers" or "Orders"). Tables contain records (rows) with data.
In this tutorial we will use the well-known Northwind sample database (included in MS Access and MS SQL Server).
Most of the actions you need to perform on a database are done with SQL statements.
The following SQL statement selects all the records in the "Customers" table:
Why semicolon is used after SQL statements:
Semicolon is used to separate SQL statements. It is a standard way to separate SQL statements in a database system in which more than one SQL statements are used in the same call.
In this tutorial, we will use semicolon at the end of each SQL statement.
SELECT- extracts data from a database
UPDATE- updates data in a database
DELETE- deletes data from a database
INSERT INTO- inserts new data into a database
CREATE DATABASE- creates a new database
ALTER DATABASE- modifies a database
CREATE TABLE- creates a new table
ALTER TABLE- modifies a table
DROP TABLE- deletes a table
CREATE INDEX- creates an index (search key)
DROP INDEX- deletes an index