What is a view?

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: - When two processes are waiting to update the rows of a table which are locked by another process, the situation is called a deadlock - The reasons for it to happen are: * lack of proper row lock commands * Poor design of front-end application - It reduces the performance of the server severely - These locks get automatically released automatically when a commit/rollback operation is performed or any process is killed externally

Correct Answer: There is a decent page in the php manual on the subject, in short mysql_pconnect() makes a persevering association with the database which implies a SQL join that don't close when the execution of your script closes mysql_connect()provides just for the database new association while utilizing mysql_pconnect , the capacity would first attempt to locate a (relentless) connection that is as of now open with the same host, username and password On the off chance that one is found, an identifier for it will be returned as opposed to opening another connection the connection with the SQL server won't be terminated when the execution of the script ends Rather, the link will stay open for future use

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: A synonym can be called as an alias for a table, view, sequence or program unit It is basically of two types: - Private - Only the owner can access it - Public - Can be accessed by any database user

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