SHASHANGKA SHEKHAR'S BLOG

Author, TechWriter

What is Index?

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An index is a physical structure containing pointers to the data. Indices are created in an existing table to locate rows more quickly and efficiently. Read More

What is View?

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A simple view can be thought of as a subset of a table. It can be used for retrieving data, as well as updating or deleting rows. Rows updated or deleted in the view are updated or deleted in the table the view was created with. It should also be noted that as data in the original table changes, so does data in the view, as views are the way to look at part of the original table.

The results of using a view are not permanently stored in the database. The data accessed through a view is actually constructed using standard T-SQL select command and can come from one to many different base tables or even other views.

What is Trigger?

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A trigger is a SQL procedure that initiates an action when an event (INSERT, DELETE or UPDATE) occurs.

Triggers are stored in and managed by the DBMS.Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion. Read More

What is Stored Procedure?

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A stored procedure is a named group of SQL statements that have been previously created and stored in the server database.

Stored procedures accept input parameters so that a single procedure can be used over the network by several clients using different input data. And when the procedure is modified, all clients automatically get the new version.

Stored procedures reduce network traffic and improve performance. Stored procedures can be used to help ensure the integrity of the database.

What are different normalization forms?

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1NF: Eliminate Repeating Groups
Make a separate table for each set of related attributes, and give each table a primary key. Each field contains at most one value from its attribute domain.

2NF: Eliminate Redundant Data
If an attribute depends on only part of a multi-valued key, remove it to a separate table.

3NF: Eliminate Columns Not Dependent On Key 
If attributes do not contribute to a description of the key, remove them to a separate table. All attributes must be directly dependent on the primary key Read More