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
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.
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 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 is Index Cluster?
A Cluster with an index on the Cluster Key
When does a Transaction end?
When it is committed or Rollbacked.
What is the effect of setting the value "ALL_ROWS" for OPTIMIZER_GOAL parameter of the ALTER SESSION command ? What are the factors that affect OPTIMIZER in choosing an Optimization approach ?
The OPTIMIZER_MODE initialization parameter Statistics in the Data Dictionary the OPTIMIZER_GOAL parameter of the ALTER SESSION command hints in the statement.
