SansSQL

Thursday, June 12, 2008

What are different normalization forms?

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
BCNF: Boyce-Codd Normal Form
If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables

What is normalization?

Database normalization is a data design and organization process applied to data structures based on rules that help build relational databases. In relational database design, the process of organizing data to minimize redundancy. Normalization usually involves dividing a database into two or more tables and defining relationships between the tables. The objective is to isolate data so that additions, deletions,and modifications of a field can be made in just one table and then propagated through the rest of the database via the defined relationships.

What is RDBMS?

Relational Data Base Management Systems (RDBMS) are database management systems that maintain data records and indices in tables. Relationships may be created and maintained across and among the data and tables. In a relational database, relationships between data items are expressed by means of tables. Interdependencies among these tables are expressed by data values rather than by pointers.This allows a high degree of data independence. An RDBMS has the capability to recombine the data items from different files, providing powerful tools for data usage.

Saturday, June 7, 2008

Stored Proc to list all object dependencies

EXEC sp_depends 'Object Name'
Go
sp_depends displays information about database object dependencies.
sp_depends displays two result sets. First One shows the objects on which the 'given
object' depends and the second shows the objects that depend on the 'given object'

Friday, June 6, 2008

Query to Check if a table is system table or User table

SELECT OBJECTPROPERTY(OBJECT_ID('TableName'), 'IsMSShipped')
0 --> Indicates User Table
1 --> Indicates System Table

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