What is the difference between a primary index and a
secondary index? What is a duplicate data entry in an index?
Can a primary index contain duplicates?
- 5 Answers
- 30738 Views
- IBM, I also Faced
- E-Mail Answers
Answer Posted / khadija
1.A primary index is an index on a set of fields that includes the unique primary key for the field and is guaranteed not to contain duplicates. A Secondary index is an index that is not a primary index and may have duplicates.
2.Example,
Employee ID can be Example of it. Example,
Employee name can be example of it. Because Employee name can have similar values.
3.The primary index contains the key fields of the table. The primary index is automatically created in the database when the table is activated. If a large table is frequently accessed such that it is not possible to apply primary index sorting, you should create secondary indexes for the table.
4.The index in which the sort order of a search key is similar
to the sort order of a relation then the index is called
primary index. Ex, front index of the book. While in secondary index the order of the search key is in
different order from the order of the key in file. Ex, index
in back side of some book.
5.In the case of
Primary Index both keys and addresses of the records are
kept in order to search a particular record faster. In the case of Secondary Index only the addresses of the
records are kept in the index not the key.
6.There can be only one primary index. There can be many secondary indices.
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
Explain about post-relational databases?
What are the types of database model?
I HAVE A PI ON COL A THE NEXT DAY I WANT CHANGE THE PI ON COL B? PLS SEND ME THE ANS
How to customize error conditions.
What are the 18 schemas?
Which four data types cannot be used as a return type from a user-defined function?
How to use online Backups?
Explain the rollup operator?
How is data stored in dbms?
Explain about normal forms?
You have a table with three columns: amount1, amount2, and amount3 in a single row only one of these three columns will have a value and the other two will be null. Write a sql query to retrieve the values from these columns?
Who are naive users?
Who are end users in dbms?
Hi , any one can help me on the same,this is regarding the Informatica Function doc,i want to know how developer is will develop the mapping. pl forwar the any function doc .just for my references. svlc75@yahoo.co.in
What is database design and development?
