Oracle Interview Questions – Set 03

Can you create a synonym without having a table?

Yes. We can create a synonym without having a base table.

How do you store pictures in a database?

Yes, you can store pictures in a database using Long Raw Data type. This data type is used to store binary data for 2 gigabytes of length. However, the table can have only one Long Raw data type.

What are the extensions used by Oracle reports?

Oracle reports are use to make business enable with the facility to provide information of all level within or outside in a secure way. Oracle report uses REP files and RDF file extensions.

What is Logical backup in Oracle?

Logical backup is used to read a set of database records and writing them into a file. An Export utility is used to take the backup while an Import utility is used to recover from the backup.

How to convert a string to a date in Oracle database?

Syntax: to_date (string , format)

Let us take an example :

to_date (‘2012-12-12’, ‘YYYY/MM/DD’)
It will return December 12, 2012.

What is the use of INDEXES option in IMP command?

The INDEXES option is used to determine whether indexes are imported.

What is save point in Oracle database?

Save points are used to divide a transaction into smaller parts. It allows rolling back of a transaction. Maximum five save points are allowed. It is used to save our data, whenever you encounter an error you can roll back from the point where you save your SAVEPOINT.

What do you understand by Redo Log file mirroring?

Mirroring is a process of having a copy of Redo log files. 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. If the group fails, the database automatically switches over to the next group. It diminishes the performance.

What is BLOB data type in Oracle?

BLOB data type is a data type with varying length binary string. It is used to store two gigabytes memory. For BLOB data type, the length needs to be specified in bytes.

How do you find current date and time in Oracle?

The SYSDATE() function is used in Oracle to find the current date and time of operating system on which the database is running.

SELECT TO_CHAR (SYSDATE, ‘MM-DD-YYYY HH24:MI:SS’) “Current_Date” FROM DUAL;