ORACLE DBA INTERVIEW QUESTIONS AND ANSWERS
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Oracle database is comprised of three types of files. One or more datafiles, two or more redo log files, and one or more control files.
92. What is database link?
A database link is a named object that describes a “path” from one database to another.
93. What are the types of database links?
Private database link, public database link & network database link.
94. What is private database link?
Private database link is created on behalf of a specific user. A private database link can be used only when the owner of the link specifies a global object name in a SQL statement or in the definition of the owner’s views or procedures.
95. What is public database link?
Public database link is created for the special user group PUBLIC. A public database link can be used when any user in the associated database specifies a global object name in a SQL statement or object definition.
96. What is network database link?
Network database link is created and managed by a network domain service. A network database link can be used when any user of any database in the network specifies a global object name in a SQL statement or object definition.
97. What is data block?
Oracle database’s data is stored in data blocks. One data block corresponds to a specific number of bytes of physical database space on disk.
98. How to define data block size?
A data block size is specified for each Oracle database when the database is created. A database users and allocated free database space in Oracle data blocks. Block size is specified in init.ora file and cannot be changed latter.
99. What is an extent?
An extent is a specific number of contiguous data blocks, obtained in a single allocation and used to store a specific type of information
100. What is dictionary cache?
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