Database Interview Questions
10 Apr, 2007
- What is Restricted Mode of Instance Startup? - An instance can be started in (or later altered to be in) restricted mode so that when the database is open connections are limited only to those whose user accounts have been granted the RESTRICTED SESSION system privilege.
- What is Partial Backup? - A Partial Backup is any operating system backup short of a full backup, taken while the database is open or shut down.
- What is Mirrored on-line Redo Log? - A mirrored on-line redo log consists of copies of on-line redo log files physically located on separate disks, changes made to one member of the group are made to all members.
10 Apr, 2007
- What are the type of Synonyms? - There are two types of Synonyms Private and Public
- What is a Redo Log? - The set of Redo Log files YSDATE,UID,USER or USERENV SQL functions, or the pseudo columns LEVEL or ROWNUM.
- What is an Index Segment? - Each Index has an Index segment that stores all of its data.
- Explain the relationship among Database, Tablespace and Data file.? - Each databases logically divided into one or more tablespaces one or more data files are explicitly created for each tablespace
10 Apr, 2007
- 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.
10 Apr, 2007
- What is Rollback Segment? - A Database contains one or more Rollback Segments to temporarily store “undo” information.
- What are the Characteristics of Data Files? - A data file can be associated with only one database. Once created a data file can’t change size. One or more data files form a logical unit of database storage called a tablespace.
- 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 datablocks. Block size is specified in INIT.ORA file and can’t be changed latter.
10 Apr, 2007
- What does ROLLBACK do? - ROLLBACK retracts any of the changes resulting from the SQL statements in the transaction.
- What is SAVE POINT? - For long transactions that contain many SQL statements, intermediate markers or savepoints can be declared which can be used to divide a transaction into smaller parts. This allows the option of later rolling back all work performed from the current point in the transaction to a declared savepoint within the transaction.
- What are the values that can be specified for OPTIMIZER MODE Parameter? - COST and RULE.
