What is a synonym? What are its various types?

Correct Answer: - These are the Logical Storage Units into which a database is divided - It is used to group together the related logical structures

Correct Answer: It is virtual table which is defined as a stored procedure based on one or more tables

Correct Answer: - Rename : It is a permanent name provided to a table or column - Alias : It is a temporary name provided to a table or column which gets over after the execution of SQL statement

Correct Answer: - TABLES - VIEWS - INDEXES - SYNONYMS - SEQUENCES - TABLESPACES

Correct Answer: Control File is used for: - Database recovery - Whenever an instance of an ORACLE database begins, its control file is used to identify the database and redo log files that must be opened for database operation to go ahead

Correct Answer: - Sub Query also termed as Nested Query or Inner Query is used to get data from multiple tables - A sub query is added in the where clause of the main query There can be two types of subqueries: a) Correlated sub query : - It can reference column in a table listed in the from list of the outer query but is not as independent as a query b) Non-Correlated sub query : - Results of this sub query are submitted to the main query or parent query - It is independent like a query

Correct Answer: Oracle database comprises of three kinds of files: - Datafiles - Redo log files - Control files

Correct Answer: - The process of having a copy of redo log files is called mirroring - It is done by creating group of log files together This ensures that LGWR automatically writes them to all the members of the current on-line redo log group - In case a group fails, the database automatically switches over to the next group It diminishes the performance

Correct Answer: - A stored procedure can accept parameters while a trigger cannot - A trigger can?t return any value while stored procedures can - A trigger is executed automatically on some event while a stored procedure needs to be explicitly called - Triggers are used for insertions, update and deletions on tables while stored procedures are often using independently in the database - A trigger cannot be written in a stored procedure However, the reverse is not possible

Correct Answer: Row Level Trigger : Row Level Trigger is fired each time row is affected by Insert, Update or Delete command If statement doesn?t affect any row, no trigger action happens Statement Level Trigger : This kind of trigger fires when a SQL statement affects the rows of the table The trigger activates and performs its activity irrespective of number of rows affected due to SQL statement