SQL server Interview Question – Part 3


SQL server Interview Question – Part 3

What is Normalization?
Normalization is a data design and organizes process to data structures based on rules that help building relational database. The process of organizing data and relational database design to minimize redundancy is called as normalization. Normalization usually includes dividing a database into two or more tables and it defining relationships between the tables.   
What are different normalization forms?
1.        First Normal Form
Make a different tale for each set of related attributes, and give every one table a primary key. Every one field contains at most one value from its attribute domain.
2.        Second Normal Form
If an attribute depends on only part of a multi values key, delete it to a different table.
3.        Third Normal Form
If element do not contribute to a description of the key, delete them to a different table. All elements must be directly dependent on the primary key.
4.        Boyce-Codd Normal Form (BCNF)
If there are non-trivial dependencies between candidates key elements, different them out into distinct tables.

What is De-normalization?
De-normalization is the process of endeavor to optimize the performance of the database. De-normalization is sometimes necessary because current DBMS implement the relational model poorly. It is a technique to move from high to low normal forms of database modeling in order to speed up database access.
What is Index?
It is a physical structure containing pointers to the data. Index is using an existing table to locate rows more quickly and efficiently. Index is possible to create an index on one or more column in a table. We can provide name each index created. The users can’t see where index is created. User just used to speed up queries. Powerful indexes are one of the best ways to improve performance in a database.
What is Collation?
It refers to a set of rules that determine how data is sorted and compare. Character data is sorted using rules that define the correct character sequence, with options for accent marks, kana character types, specifying case sensitivity.


What is Stored Procedure?
A stored procedure is SQL statements that have been created and stored in the server database. It accepts input parameters so that a single procedure can be used over the network by several users using separate input data. When the procedure is modified, all users automatically get the new version. Stored procedures improve performance reducing network traffic.
What is a linked Server?
Linked Servers using we can add other SQL server to group and query both the SQL server dbs using T-SQL statements. You can create very easy to follow, SQL statements that allow remote data to be retrieved, combined with local data.
What is View?
Using view you can retrieve data as well as updating or deleting rows. The view was created with updated or deleted in the table. View should also be noted that as data in the original table changes, so does data in the view. View result is not permanently stored in the database.
What is Cursor?
Cursor is a database object. It used by applications to manipulate data in a set on a row-by-row basis, alternatively of the typical SQL commands that operate on all the rows in the set at one time.
Following order we need to perform some steps with a cursor
·       Declare cursor
·       Open cursor
·       Fetch row from the cursor
·       Process fetched row
·       Close cursor
·       Deal locates cursor.
What is Identity?
Identity is a column that automatically creates numeric values. You can set start and increment values. A GUID column also creates numbers; the value of this can’t be controlled.


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