SQL supports three types of tables: base tables, derived tables, and viewed tables. Using the Internet as a resource, research the four types of base tables, name them, provide a description of what they are, how they work, and why they are needed.

User tables are the most important base tables, because they contain data that can be used later. They can be stored in hard drive and can also be deleted if you want.

[]Local temporary tables are the base tables that are stored in the "tempdb" folder. They are only available to the session where it was created. These base tables are self deleted once that session is over. They are denoted by #

[]Global temporary tables are base tables stored in "tempdb" folder also. But they are available not just to all sessions but also to all users. However, they are self removed when the temporary table has been completed at he last session. They are denoted by ##

[]Table variables are base tables used as alternatives to temporary tables used to store a set of records. The syntax of a table variable include: Insert into, select from, declare, etc.

DESCRIPTION

These tables are made of unique metadata that can be used anywhere in the SQL server.

These base tables are system based and are not for the general use, but are only used within the SQL Server Database Engine.

HOW THEY WORK

Base table is a structure that allows you to input and store records. Once the required table has been mapped as PROJECT Table, accessing the data using SQL statements becomes possible.

WHY ARE THEY NEEDED?

SQL base tables are used to uniquely search out individual row in the database. These base tables helps to ensure that two rows don't have the same value of primary key.

Practically, this means that by just knowing the primary key of a particular row, you can select every single row easily.