Creation of indexes, Database Management System

Assignment Help:

Creation of Indexes

Automatically: When a primary key or Unique constraint is show in a table definition then a unique index is formed automatically.

Manually: User can form non-unique indexes on columns to speed up access time to rows.

Example: The following commands produce index on employee name and employee name + department number respectively.

CREATE INDEX EMP_ENAME_IDX ON EMP (ENAME);

CREATE INDEX EMP_MULTI_IDX ON EMP (ENAME, DEPTNO);

Finding facts about created indexes: The data dictionary have the name of index, table name and column names. For instance, in Oracle a user-indexes and user-ind-columns see contains the details about user formed indexes.

Remove an index from the data dictionary:

DROP INDEX EMP_ENAME_IDX;

Indexes cannot be modified.


Related Discussions:- Creation of indexes

Guidelines for creation of table, Guidelines for creation of table: ...

Guidelines for creation of table: Table name should begin with an alphabet. In table name, single quotes and blank spaces are not allowed. Reserve words of that DBM

Describe the concepts of structural semantic data model, Question 1 List a...

Question 1 List and explain various Normal Forms. How BCNF differs from the Third Normal Form and 4th Normal forms? Question 2 Describe the concepts of Structural Semantic Da

Give detail description on transactions, Give detail description on Transac...

Give detail description on Transactions. - Using transactions we can group all SQL commands into a single unit. - Transaction begins with some task and finishes only when a

Explain the object-oriented decomposition, Explain the Object-oriented deco...

Explain the Object-oriented decomposition Object-oriented decomposition targets at identifying individual sovereign objects that encapsulate both a state and certain behavio

Describe physical data independence, Describe Physical Data independence ? ...

Describe Physical Data independence ? Physical Data Independence - It is capacity to modify the internal schema without having to change conceptual schema. Therefore, the exter

Explain the dependency relationship of object oriented, Explain the depende...

Explain the dependency relationship of object oriented A dependency is a relationship which states that a change in specification of one thing can affect another thing, but n

Describe the capabilities offered via mysql client apis, Describe the capab...

Describe the capabilities offered via MySQL client APIs? . • Checking for errors. . • Connecting to the MySQL server, selecting a database, disconnecting from the server

Explain query tree represent relational algebra expression, How does a quer...

How does a query tree represent a relational algebra expression?      Ans: This includes transforming an initial expression (tree) into an equivalent expression (tree) that is

Describe the relational model, a) Distinguish between ‘database' and ‘Data...

a) Distinguish between ‘database' and ‘Database Management Systems (DBMS)'. b) List and briefly describe five potential benefits of the database approach compared to conventio

Difference between sql and sql*plus, Difference between SQL and SQL*Plus ...

Difference between SQL and SQL*Plus SQL SQL*Plus SQL is a language SQL *Plus is an environment It   is   bas

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd