Java Reference
In-Depth Information
Introduction
Most commercial software products use databases in some way. Databases are specially
built software products which have been design to hold huge quantity of data. Some popular
databases in the market include Oracle (from Oracle Corporation), SQL Server (from Mi-
crosoft) etcThe database is organized into database tables and each table can have many
columns. Apart from tables, a database can also have database triggers, sequences, functions
etc. You can create data, store data, modify data or delete data which may be residing in-
side a database. For doing these operations, a query language is used. This query language is
commonly known as Structured Query Language (SQL). Each database engine understands
its own version of SQL. But SQL syntax is not very different from one version to another.
You can create a script consisting of SQL statements and execute it after connecting to the
database engine.
Let us see some examples of SQL statements:
•
A select statement - Select <column name1, 2..> from <table name> where
<condition>. This statement will fetch number of rows of data of columns
from the table meeting condition requirements.
•
A create statement - Create table <table mane> with <column name 1, 2..>
•
A delete statement - Delete from table <table name> where >condition>
•
A insert statement - Insert into table <table name> <column name 1, 2..>
values (1, 2, ..)
