Oracle Interview Questions and Answers
Question - 31 : - What is Table ?
Answer - 31 : - A table is the basic unit of data storage in an ORACLE database. The tables of a database hold all of the user accessible data. Table data is stored in rows and columns.
Question - 32 : - Can a view based on another view?
Answer - 32 : - Yes.
Question - 33 : - What are the advantages of views?
Answer - 33 : - - Provide an additional level of table security, by restricting access to a predetermined set of rows and columns of a table.
- Hide data complexity.
- Simplify commands for the user.
- Present the data in a different perspective from that of the base table.
- Store complex queries.
Question - 34 : - What is an Oracle sequence?
Answer - 34 : - A sequence generates a serial list of unique numbers for numerical columns of a database's tables.
Question - 35 : - What is a synonym?
Answer - 35 : - A synonym is an alias for a table, view, sequence or program unit.
Question - 36 : - What are the types of synonyms?
Answer - 36 : - There are two types of synonyms private and public.
Question - 37 : - What is a private synonym?
Answer - 37 : - Only its owner can access a private synonym.
Question - 38 : - What is a public synonym?
Answer - 38 : - Any database user can access a public synonym.
Question - 39 : - What are synonyms used for?
Answer - 39 : - - Mask the real name and owner of an object.
- Provide public access to an object
- Provide location transparency for tables, views or program units of a remote database.
- Simplify the SQL statements for database users.
Question - 40 : - What is an Oracle index?
Answer - 40 : - An index is an optional structure associated with a table to have direct access to rows, which can be created to increase the performance of data retrieval. Index can be created on one or more columns of a table.