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

What is functional dependency, A Functional dependency is described by ...

A Functional dependency is described by X Y between two groups of attributes Y and X that are subsets of R specifies a constraint on the possible tuple that can make a relation

Cost of reading a file , A file of employee have 10,000 blocks on a cylinde...

A file of employee have 10,000 blocks on a cylinder of a disk with characteristics r=8ms and btt=0.6ms I want to know the cost of read inthe file under following conditions for a q

Explain the functional mode with help of an example, Explain the Functional...

Explain the Functional Mode with help of an example. Functional Model  The functional model shows a computation and functional derivation of data values in it without ind

Database, 3. (10 points) Assume that you have been presented with the follo...

3. (10 points) Assume that you have been presented with the following relation for the Baxter Aviation database: Charters (Pilot#, Pilot name, Aircraft ID#, #seats, Village, Fligh

Describe the composite key, Describe the Composite Key Composite Key: ...

Describe the Composite Key Composite Key: Sometimes one key is not enough to uniquely recognize a row. E.g. in a single class Roll is enough to search a student, but in the w

Problem about data mining for business intelligence, Do the 11.1 11.1 Cre...

Do the 11.1 11.1 Credit Card Use. Consider the following hypothetical bank data on consumers’ use of credit card credit facilities in Table 11.3. Create a small worksheet in Exce

What are the different approaches for database design, What are the differe...

What are the different approaches for database design? There are two basic approaches for database design which are as follows: Attribute driven: It compiles a list of att

Describe logical data independence, Describe logical data independence ? ...

Describe logical data independence ? Logical Data Independence - It is the capacity to modify the conceptual schema without having to change external schemas or application p

Explain interfaces for parametric users, Explain Interfaces for parametric ...

Explain Interfaces for parametric Users? Interfaces for Parametric Users - Parametric users, such as bank tellers, frequent have a little set of operations in which they must p

Scope of traffic data management, A TDMS project plan is not a typical Info...

A TDMS project plan is not a typical Information Technology project plan; therefore, a traffic data project has several unique characteristics: Traffic data management system

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