'Performance tuning' is the term used to improve the performance of a query..that is, quickening the query execution time...a query that involves a large no of db tables may take around 20-30 min to execute for ex... In such case, the developer shud fine...
Differ between DECODE and CASE. DECODE and CASE statements are very similar, but CASE is extended version of DECODE. DECODE does not allow Decision making statements in its place. select decode(totalsal=12000,’high’,10000,’medium’) as decode_tesr from...
Explain autonomous transaction. An autonomous transaction is an independent transaction of the main or parent transaction. It is not nested if it is started by another transaction. There are several situations to use autonomous transactions like event...
What is the importance of SQLCODE and SQLERRM? SQLCODE returns the value of the number of error for the last encountered error whereas SQLERRM returns the message for the last error
Explain Commit, Rollback and Savepoint. For a COMMIT statement, the following is true: Other users can see the data changes made by the transaction. The locks acquired by the transaction are released. The work done by the transaction becomes permanent....
What are the cursor attributes used in PL/SQL? %ISOPEN: it checks whether the cursor is open or not. %ROWCOUNT: returns the number of rows affected by DML operations: INSERT,DELETE,UPDATE,SELECT. %FOUND: it checks whether cursor has fetched any row. If...
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What is the difference between FUNCTION, PROCEDURE AND PACKAGE in PL/SQL? Function: The main purpose of a PL/SQL function is generally to compute and return a single value. A function has a return type in its specification and must return a value specified...
%TYPE and %ROWTYPE %TYPE is used to declare a variable that is of the same type as a specified table’s column. Emp_number emp.empno%type; %ROWTYPE is used to declare a record(variable that represents the entire row of a table). Emp_record emp%rowtype...
What are the advantages and disadvantages of merge replication? Advantages It provides built-in and custom conflict resolution capabilities. It allows for the synchronization of data from multiple tables at one time. It provides rich data replication...
What are the advantages and disadvantages of merge replication? Advantages It provides built-in and custom conflict resolution capabilities. It allows for the synchronization of data from multiple tables at one time. It provides rich data replication...
