Oracle DBA Interview questions and Answers
Differentiate between TRUNCATE and DELETE.
The Delete command will log the data changes in the log file where as the truncate will simply remove the data without it. Hence Data removed by Delete command can be rolled back but not the data removed by TRUNCATE. Truncate is a DDL statement whereas DELETE is a DML statement.
What is the maximum buffer size that can be specified using the DBMS_OUTPUT.ENABLE function?
Can you use a commit statement within a database trigger?
Yes, if you are using autonomous transactions in the Database triggers.
What is an UTL_FILE? What are different procedures and functions associated with it?
The UTL_FILE package lets your PL/SQL programs read and write operating system (OS) text files. It provides a restricted version of standard OS stream file input/output (I/O).
Difference between database triggers and form triggers?
Database triggers are fired whenever any database action like INSERT, UPATE, DELETE, LOGON LOGOFF etc occurs. Form triggers on the other hand are fired in response to any event that takes place while working with the forms, say like navigating from one field to another or one block to another and so on.
What is OCI. What are its uses?
OCI is Oracle Call Interface. When applications developers demand the most powerful interface to the Oracle Database Server, they call upon the Oracle Call Interface (OCI). OCI provides the most comprehensive access to all of the Oracle Database functionality. The newest performance, scalability, and security features appear first in the OCI API. If you write applications for the Oracle Database, you likely already depend on OCI. Some types of applications that depend upon OCI are:
What are ORACLE PRECOMPILERS?
A precompiler is a tool that allows programmers to embed SQL statements in high-level source programs like C, C++, COBOL, etc. The precompiler accepts the source program as input, translates the embedded SQL statements into standard Oracle runtime library calls, and generates a modified source program that one can compile, link, and execute in the usual way. Examples are the Pro*C Precompiler for C, Pro*Cobol for Cobol, SQLJ for Java etc.
What is syntax for dropping a procedure and a function? Are these operations possible?
Drop Procedure/Function ; yes, if they are standalone procedures or functions. If they are a part of a package then one have to remove it from the package definition and body and recompile the package.
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