Category Archives: oracle

Define the order of priority when executing sql statements ?

  Order Evaluated Operator 1 Arithmetic operators (*, /, +, -) 2 Concatenation operators (||) 3 Comparison conditions 4 Is[NOT] NULL, LIKE, [NOT] IN 5 [NOT] BETWEEN 6 NOT Logical condition 7 AND logical condition 8 OR logical condition Advertisements

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What is ROW_NUMBER() function in oracle ?

Before knowing the ROW_NUMBER() function we need to understand the oracle analytical functions: Analytical means to get more control & allowing to operate within a table’s column or data like: Analytical functions also know as windowing functions. it mostly used … Continue reading

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What is difference between dbms_jobs & dbms_scheduler in oracle ?

Simply first, DBMS_JOBS is old version & DBMS_SCHEDULER  is new version having powerful syntax , user restriction to access the scheduler ,features as below: logging of job runs (job history) simple but powerful scheduling syntax (similar to but more powerful … Continue reading

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Oracle most used string functions

S.No Function & Purpose 1 ASCII(x); Returns the ASCII value of the character x. 2 CHR(x); Returns the character with the ASCII value of x. 3 CONCAT(x, y); Concatenates the strings x and y and returns the appended string. 4 … Continue reading

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Types of constraints available in oracle

There are five types of constraint available in oracle as following: NOT NULL: NOT NULL Constraint ensures that the column contains no null values. UNIQUE KEY: UNIQUE Key Constraint ensures that every value in a column or set of columns must be … Continue reading

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What is sys_refcursor in oracle ?

SYS_REFCURSOR is a pointer to result set of query where you allow the client to fetch many or a few records as per requirement. You will need the SYS_REFCURSOR whenever it require to fetch records from stored procedures. Using REF CURSOR s is one … Continue reading

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What is pragma sql in oracle ?

In Oracle PL/SQL, PRAGMA refers to a compiler directive or “hint” it is used to provide an instruction to the compiler. The directive restricts member subprograms to query or modify database tables and packaged variables. Pragma directives are processed at compile time … Continue reading

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