Frequently asked basic and advanced Oracle Database Interview Questions and Answers on Database theory and SQL Queries with Examples for Freshers and Experienced DBA, Java, PHP, .Net Developers.
1) What is oracle database ?
Oracle Database is a relational database management system (RDBMS) which is used to store and retrieve the large amounts of data. Oracle Database had physical and logical structures. Logical structures and physical structures are separated from each other
Oracle Database is a relational database management system (RDBMS) which is used to store and retrieve the large amounts of data. Oracle Database had physical and logical structures. Logical structures and physical structures are separated from each other
2) What is schema?
A user account and its associated data including tables, views, indexes, clusters, sequences,procedures, functions, triggers,packages and database links is known as Oracle schema. System, SCOTT etc are default schema's. We can create a new Schema/User. But we can't drop default database schema's.
A user account and its associated data including tables, views, indexes, clusters, sequences,procedures, functions, triggers,packages and database links is known as Oracle schema. System, SCOTT etc are default schema's. We can create a new Schema/User. But we can't drop default database schema's.
3) What is a Tablespace?
Oracle use Tablespace for logical data Storage. Physically, data will get stored in Datafiles. Datafiles will be connected to tablespace. A tablespace can have multiple datafiles. A tablespace can have objects from different schema's and a schema can have multiple tablespace's. Database creates "SYSTEM tablespace" by default during database creation. It contains read only data dictionary tables which contains the information about the database.
Also Read Basic to Advanced Oracle SQL Query Interview Question and Answers
Oracle use Tablespace for logical data Storage. Physically, data will get stored in Datafiles. Datafiles will be connected to tablespace. A tablespace can have multiple datafiles. A tablespace can have objects from different schema's and a schema can have multiple tablespace's. Database creates "SYSTEM tablespace" by default during database creation. It contains read only data dictionary tables which contains the information about the database.
Also Read Basic to Advanced Oracle SQL Query Interview Question and Answers
4) What is a Control File ?
Control file is a binary file which stores Database name, associated data files, redo files, DB creation time and current log sequence number. Without control file database cannot be started and can hamper data recovery.
Control file is a binary file which stores Database name, associated data files, redo files, DB creation time and current log sequence number. Without control file database cannot be started and can hamper data recovery.
5) Define data blocks ?
Data Blocks are the base unit of logical database space. Each data block represents a specific number of bytes of database space on a disk
6) What is an Extent ?
Extent is a collection of Continuous data blocks, which is used for storing a specific type of information.
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7) What is a Segment ?
A segment is a collection of extends which is used for storing a specific data structure and resides in the same tablespace.
8) What is Rollback Segment ?
Database contain one or more Rollback Segments to roll back transactions and data recovery.
Data Blocks are the base unit of logical database space. Each data block represents a specific number of bytes of database space on a disk
6) What is an Extent ?
Extent is a collection of Continuous data blocks, which is used for storing a specific type of information.
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7) What is a Segment ?
A segment is a collection of extends which is used for storing a specific data structure and resides in the same tablespace.
8) What is Rollback Segment ?
Database contain one or more Rollback Segments to roll back transactions and data recovery.
9) What are the different type of Segments ?
Data Segment(for storing User Data), Index Segment (for storing index), Rollback Segment and Temporary Segment.
Data Segment(for storing User Data), Index Segment (for storing index), Rollback Segment and Temporary Segment.
10) What is a Redo Log ?
Redo Log files is a
collection of 2 or more pre-allocated files, which is used in data
recovery. When ever a change is made to the database, change info gets
stored in redo files. In case of a database crash, we can used redo
files for data recovery.
