10 Apr, 2007
Database Interview Questions
- What is 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.
- What is a Synonym? - A synonym is an alias for a table, view, sequence or program unit.
- What is a Sequence? - A sequence generates a serial list of unique numbers for numerical columns of a database’s tables.
- What is a Segment? - A segment is a set of extents allocated for a certain logical structure.
- What is schema? - A schema is collection of database objects of a User.
- Describe Referential Integrity? - A rule defined on a column (or set of columns) in one table that allows the insert or update of a row only if the value for the column or set of columns (the dependent value) matches a value in a column of a related table (the referenced value). It also specifies the type of data manipulation allowed on referenced data and the action to be performed on dependent data as a result of any action on referenced data.
- What is Hash Cluster? - A row is stored in a hash cluster based on the result of applying a hash function to the row’s cluster key value. All rows with the same hash key value are stores together on disk.
- What is a Private Synonyms? - A Private Synonyms can be accessed only by the owner.
- What is Database Link? - A database link is a named object that describes a “path” from one database to another.
- What is a Tablespace? - A database is divided into Logical Storage Unit called tablespaces. A tablespace is used to grouped related logical structures together
