-
What is a Synonym ?
A synonym is an alias for a table, view, sequence or program unit.
-
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.
-
What is a Segment ?
A segment is a set of extents allocated for a certain logical structure.
-
What is a Data File ?
Every ORACLE database has one or more physical data files. A database's data files contain all the database data. The data of logical database structures such as tables and indexes is physically stored in the data files allocated for a database.
-
What are the Referential actions supported by FOREIGN KEY integrity constraint ?
UPDATE and DELETE Restrict - A referential integrity rule that disallows the update or deletion of referenced data.DELETE Cascade - When a referenced row is deleted all associated dependent rows are deleted.
-
What is difference between UNIQUE constraint and PRIMARY KEY constraint ?
A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls.
-
What are the Limitations of a CHECK Constraint ?
The condition must be a Boolean expression evaluated using the values in the row being inserted or updated and can't contain sub queries, sequence, the SYSDATE,UID,USER or USERENV SQL functions, or the pseudo columns LEVEL or ROWNUM.
-
What are the uses of Rollback Segment ?
Rollback Segments are used :To generate read-consistent database information during database recovery to rollback uncommitted transactions for users.
-
What is SYSTEM tablespace and when is it Created?
Every ORACLE database contains a tablespace named SYSTEM, which is automatically created when the database is created. The SYSTEM tablespace always contains the data dictionary tables for the entire database.
-
What is a Tablespace?
A database is divided into Logical Storage Unit called tablespaces. A tablespace is used to grouped related logical structures together.
-
What does a Control file Contain ?
A Control file records the physical structure of the database. It contains the following information.Database NameNames and locations of a database's files and redolog files.Time stamp of database creation.
-
What is a Data Dictionary ?
The data dictionary of an ORACLE database is a set of tables and views that are used as a read-only reference about the database.It stores information about both the logical and physical structure of the database, the valid users of an ORACLE database, integrity constraints defined for tables in the database and space allocated for a schema object and how much of it is being used.
-
What is an Integrity Constrains ?
An integrity constraint is a declarative way to define a business rule for a column of a table.
-
What is the use of Control File ?
When an instance of an ORACLE database is started, its control file is used to identify the database and redo log files that must be opened for database operation to proceed. It is also used in database recovery.
-
How are Indexes Update ?
Indexes are automatically maintained and used by ORACLE. Changes to table data are automatically incorporated into all relevant indexes.
-
-
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...
-
What is Rollback Segment ?
A Database contains one or more Rollback Segments to temporarily store "undo" information.
-
What is an Index Segment ?
Each Index has an Index segment that stores all of its data.
-
What are the different type of Segments ?
Data Segment, Index Segment, Rollback Segment and Temporary Segment.
Oracle Architecture Interview Questions
Ans