If a foreign key reference a parent key of the same table is called self-referential integrity constraint.

samiksc

 Profile Answers by samiksc Questions by samiksc

• Jan 19th, 2006

Self referential integrity constraint refers to two columns related by referential integrity which belong to the same table.For example ManagerId column in employees table is a foreign key which refers to EmployeeId in the same table.

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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.

fancyoracle

 Profile Answers by fancyoracle Questions by fancyoracle

• Aug 16th, 2007

A check constraint allows you to specify a condition on each row in a table. Note: A check constraint can NOT be defined on a VIEW. The check constraint defined on a table must refer to only columns i...

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A synonym is an alias for a table, view, sequence or program unit.

thumatinagaraju

 Profile Answers by thumatinagaraju Questions by thumatinagaraju

• Oct 24th, 2006

Ya synonym is used to rename or to create alias for the data base object ..

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Clusters are groups of one or more tables physically stores together to share common columns and are often used together.

partho sarathi konar

• Oct 1st, 2006

Clusters are groups of one or more tables physically stored together because they share common columns and are often used together. This improves disk access time.The related columns of the tables in ...

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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.

partho sarathi konar

• Oct 1st, 2006

Hash Clusters cluster table data in a manner similar to normal, index clusters. To find or store a row in a hash cluster, Oracle applies a hash function to the row's cluster key value. The resulting h...

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In Circumstances, all of the data for a row in a table may not be able to fit in the same data block. When this occurs , the data for the row is stored in a chain of data block (one or more) reserved for that segment.

feroz

• Aug 29th, 2006

If a row is too large to fit into a single database block row chaining happens. For example, if you use a 4KB blocksize for your database, and you need to insert a row of 8KB into it, Oracle will...

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An integrity constraint is a declarative way to define a business rule for a column of a table.

simakas

• Oct 5th, 2007

Special requirements for table data:1) allow NULL value2) uniqueness of value3) primary key4) foreign key5) special value size/text/length etc requirementsAll information is stored in Data Dictionary.

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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.

bahwesh

• Jul 17th, 2007

Foreign key value must exist as PK value on?some other ?table...FK?value can be null but?PK can't

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No Limit.

jjvetri

 Profile Answers by jjvetri Questions by jjvetri

• Aug 5th, 2009

You can create any number of check constraintsseparated by AND, OR, or NOT to create more complex conditions.

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Yes.

matabrez

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• Jan 10th, 2011

Yes one tablespace can hold objects from different schemas.Eg. when we create any schema (user) than we can assign default tablespace like this for any user user we can use same tablespace. Eg. SYSTE...

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Views do not contain or store data.

sanjay Pramanaik

• Oct 5th, 2006

?Hi,?? It? depends on the type of view it is.? if it is a normal view than it does not contains the data. and if it is materialsed view than it contains the data.?Thanks sanjay pramanik

kehri_anurag

 Profile Answers by kehri_anurag Questions by kehri_anurag

• Jan 13th, 2006

No, View never contain the the data, Only defination of it stores in the data base, when ever you invoke them they show you the data based on their defination.Only Materlized view or SnaptShot contain the the data.

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A sequence generates a serial list of unique numbers for numerical columns of a database's tables.

thumatinagaraju

 Profile Answers by thumatinagaraju Questions by thumatinagaraju

• Oct 24th, 2006

Nice answer soumyanag thumati_nagaraju@yahoo.co.in

soumya

• Jun 28th, 2006

A sequence is an automatically generated unique number.It is typically used to create a primary key value.It is a sharable object.Using sequence change the increment value, maximum value, minimum value, cycle option, or cache option.

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Synonyms are used to : Mask the real name and owner of an object.Provide public access to an objectProvide location transparency for tables, views or program units of a remote database.Simplify the SQL statements for database users.

harrykhokhar

 Profile Answers by harrykhokhar Questions by harrykhokhar

• Jun 1st, 2010

Synonyms are alternative names for the objects like views, indexes, etc.

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Indexes are automatically maintained and used by ORACLE. Changes to table data are automatically incorporated into all relevant indexes.

C.Ramesh

• Oct 18th, 2007

Index is a Database object . It can be accessed rows physical fast. when you move the table from different table spaces or same table spaces indexes will unusually status. So You compulsory rebuild the index. Rebuilding the index is very fast than drop and create the new indexes.

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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.

edeed

 Profile Answers by edeed Questions by edeed

• Mar 27th, 2008

A database link is a pointer that defines a one-way communication path from an Oracle Database server to another database server. The link pointer is actually defined as an entry in a data dictionary ...

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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.

Sumer

 Profile Answers by Sumer Questions by Sumer

• Jan 5th, 2006

stansard block size, which is set with parameter DB_BLOCK_SIZE cannot be changed after creating database. We can set non standard parameter size later with parameter DB_nk_BLOCK_SIZE and it can be changed.NOTE: Standard block size cnannot be equal to nonstandars block size.

NARENDER REDDY

• Jan 4th, 2006

It can be changed later also by setting block_size in init.ora like 2 or 4 or 8 or 16. this feature available from oracle 9i. it can support multi block size.

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An Extent is a specific number of contiguous data blocks, obtained in a single allocation, and used to store a specific type of information.

gaurav_varma

 Profile Answers by gaurav_varma Questions by gaurav_varma

• Jan 10th, 2007

An extent is a logical unit of database storage space allocation made up of a number of contiguous data blocks. One or more extents in turn make up a segment. When the existing space in a segment is c...

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A segment is a set of extents allocated for a certain logical structure.

gaurav_varma

 Profile Answers by gaurav_varma Questions by gaurav_varma

• Jan 10th, 2007

A segment is a set of extents that contains all the data for a specific logical storage structure within a tablespace. For example, for each table, Oracle allocates one or more extents to form that ta...

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Data Segment, Index Segment, Rollback Segment and Temporary Segment.

taraldesai

 Profile Answers by taraldesai Questions by taraldesai

• Jan 28th, 2008

Data, index , rollback, undo,cluster

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Each Index has an Index segment that stores all of its data.

taraldesai

 Profile Answers by taraldesai Questions by taraldesai

• Jan 28th, 2008

It's an oracle object as other object like table. It stores index key + rowid for that key. So when you scan index it finds respective rowid and fetch data from that rowid. and it's faster

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