Genpact Most Frequently Asked Latest Oracle Interview Questions Answers
What Is Sga?
The System Global Area in an Oracle database is the area in memory to facilitate the transfer of information between users. It holds the most recently requested structural information between users. It holds the most recently requested structural information about the database. The structure is database buffers, dictionary cache, redo log buffer and shared pool area.
What Is A Cluster Key?
The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables in the cluster.
What Are Clusters?
Group of tables physically stored together because they share common columns and are often used together is called cluster.
What Is A Control File?
Database’s overall physical architecture is maintained in a file called control file. It will be used to maintain internal consistency and guide recovery operations. Multiple copies of control files are advisable.
It Is Possible To Use Raw Devices As Data Files And What Are The Advantages Over File System Files?
The advantages over file system files are that I/O will be improved because Oracle is bye-passing the kernel which writing into disk. Disk corruption will be very less.
How Can We Plan Storage For Very Large Tables?
Limit the number of extents in the table
Separate table from its indexes.
Allocate sufficient temporary storage.
What Is A Join? Explain The Different Types Of Joins?
Join is a query, which retrieves related columns or rows from multiple tables.
Self Join – Joining the table with itself.
Equi Join – Joining two tables by equating two common columns.
Non-Equi Join – Joining two tables by equating two common columns.
Outer Join – Joining two tables in such a way that query can also retrieve rows that do not have corresponding join value in the other table.
What Is Difference Between Truncate & Delete?
TRUNCATE commits after deleting entire table i.e., cannot be rolled back.
Database triggers do not fire on TRUNCATE
DELETE allows the filtered deletion. Deleted records can be rolled back or committed.
Database triggers fire on DELETE.
What Is A Transaction?
Transaction is logical unit between two commits and commit and rollback.
What Are The Types Of Sql Statement?
Data Definition Language: CREATE, ALTER, DROP, TRUNCATE, REVOKE, NO AUDIT & COMMIT.
Data Manipulation Language: INSERT, UPDATE, DELETE, LOCK TABLE, EXPLAIN PLAN & SELECT.
Transactional Control: COMMIT & ROLLBACK.
Session Control: ALTERSESSION & SET ROLE.
System Control: ALTER SYSTEM.
What Is An Oracle Sequence?
A sequence generates a serial list of unique numbers for numerical columns of a database’s tables.
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 Are The Components Of Logical Database Structure Of Oracle Database?
There are tablespaces and database’s schema objects.
What Is Sga?
The System Global Area in an Oracle database is the area in memory to facilitate the transfer of information between users. It holds the most recently requested structural information between users. It holds the most recently requested structural information about the database. The structure is database buffers, dictionary cache, redo log buffer and shared pool area.
What Is A Cluster Key?
The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables in the cluster.
What Are Clusters?
Group of tables physically stored together because they share common columns and are often used together is called cluster.
What Is A Control File?
Database’s overall physical architecture is maintained in a file called control file. It will be used to maintain internal consistency and guide recovery operations. Multiple copies of control files are advisable.
It Is Possible To Use Raw Devices As Data Files And What Are The Advantages Over File System Files?
The advantages over file system files are that I/O will be improved because Oracle is bye-passing the kernel which writing into disk. Disk corruption will be very less.
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| Genpact Most Frequently Asked Latest Oracle Interview Questions Answers |
How Can We Plan Storage For Very Large Tables?
Limit the number of extents in the table
Separate table from its indexes.
Allocate sufficient temporary storage.
What Is A Join? Explain The Different Types Of Joins?
Join is a query, which retrieves related columns or rows from multiple tables.
Self Join – Joining the table with itself.
Equi Join – Joining two tables by equating two common columns.
Non-Equi Join – Joining two tables by equating two common columns.
Outer Join – Joining two tables in such a way that query can also retrieve rows that do not have corresponding join value in the other table.
What Is Difference Between Truncate & Delete?
TRUNCATE commits after deleting entire table i.e., cannot be rolled back.
Database triggers do not fire on TRUNCATE
DELETE allows the filtered deletion. Deleted records can be rolled back or committed.
Database triggers fire on DELETE.
What Is A Transaction?
Transaction is logical unit between two commits and commit and rollback.
What Are The Types Of Sql Statement?
Data Definition Language: CREATE, ALTER, DROP, TRUNCATE, REVOKE, NO AUDIT & COMMIT.
Data Manipulation Language: INSERT, UPDATE, DELETE, LOCK TABLE, EXPLAIN PLAN & SELECT.
Transactional Control: COMMIT & ROLLBACK.
Session Control: ALTERSESSION & SET ROLE.
System Control: ALTER SYSTEM.
What Is An Oracle Sequence?
A sequence generates a serial list of unique numbers for numerical columns of a database’s tables.
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 Are The Components Of Logical Database Structure Of Oracle Database?
There are tablespaces and database’s schema objects.