Oracle Interview Question and Answers

1. What is Oracle table?
  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.
2. What are Clusters?
  Clusters are groups of one or more tables physically stores together to share common columns and are often used together.
3. What is an Index?
  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.
4. What are the advantages of views?
 
  • 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.
5. What are the various types of queries?
 
    The types of queries are :
  • Normal Queries
  • Sub Queries
  • Co-related queries
  • Nested queries
  • Compound queries
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