Procedure and Functions in pl/sql
- Procedure Procedure Parameter in PL/SQL Methods for Passing Parameters Functions Difference between function and procedure Contents
- A procedure is a group of PL/SQL statements that you can call by name. ...
- procedure-name specifies the name of the procedure. ...
What is the difference between procedure and function in SQL?
What is the difference between “Stored Procedure” and “Function”?
- A procedure can have both input and output parameters, but a function can only have input parameters.
- Inside a procedure we can use DML (INSERT/UPDATE/DELETE) statements. But inside a function we can’t use DML statements.
- We can’t utilize a Stored Procedure in a Select statement. ...
What are the advantages of PL SQL over SQL?
What Are The Advantages Of PL/SQL Over SQL?
- Exceptions can be handled in PL/SQL where as in SQL you cannot.
- PL/SQL uses packages of functions and procedures which are simply stored in the database. And these can be used far more easily.
- Once these functions and procedures (in PL/SQL) are created, they can used anytime in the application. ...
- Batch updates possible in PL/SQL.
How can PL/SQL functions return multiple values?
PL/SQL function to return more than one value
- Concatenate return_value1 and return_value2 and return as a string (delimited by some special character) and process the string later.
- Convert the function to procedure and return result through OUT parameters . (though it is possible to do use OUT paramete in function)
- Pass Ref cursor or table type instance as return type
How to call a function in PLSQL function?
Calling PL/SQL Function: While creating a function, you have to give a definition of what the function has to do. To use a function, you will have to call that function to perform the defined task. Once the function is called, the program control is transferred to the called function.
What is a function in PL SQL?
Similar to a procedure, a PL/SQL function is a reusable program unit stored as a schema object in the Oracle Database. The following illustrates the syntax for creating a function: CREATE [OR REPLACE] FUNCTION function_name (parameter_list) RETURN return_type IS. [declarative section]
WHAT IS function and procedure in Oracle?
A procedure is a subprogram that performs a specific action. You specify the name of the procedure, its parameters, its local variables, and the BEGIN-END block that contains its code and handles any exceptions. A function is a subprogram that computes and returns a value.
What is the difference between PL SQL function and procedure?
Procedures are basic PL SQL blocks to perform a specific action. Functions are blocks used mainly to perform the computations. Functions must return the value. When you are writing functions make sure that you can write the return statement.
What is difference procedure and function?
A function would return the returning value/control to the code or calling function. The procedures perform certain tasks in a particular order on the basis of the given inputs. A procedure, on the other hand, would return the control, but would not return any value to the calling function or the code.
What is a function in Oracle?
A function is a subprogram that returns a value. The data type of the value is the data type of the function. A function invocation (or call) is an expression, whose data type is that of the function. Before invoking a function, you must declare and define it.
What is trigger in PL SQL?
A PL/SQL trigger is a named database object that encapsulates and defines a set of actions that are to be performed in response to an insert, update, or delete operation against a table. Triggers are created using the PL/SQL CREATE TRIGGER statement.
How many types of functions are there in SQL?
There are three types of user-defined functions in SQL Server: Scalar Functions (Returns A Single Value) Inline Table Valued Functions (Contains a single TSQL statement and returns a Table Set) Multi-Statement Table Valued Functions (Contains multiple TSQL statements and returns Table Set)
What is difference between stored procedure and function?
The function must return a value but in Stored Procedure it is optional. Even a procedure can return zero or n values. Functions can have only input parameters for it whereas Procedures can have input or output parameters. Functions can be called from Procedure whereas Procedures cannot be called from a Function.
Can procedure return a value?
A stored procedure does not have a return value but can optionally take input, output, or input-output parameters. A stored procedure can return output through any output or input-output parameter.
What is procedure and example?
The definition of procedure is order of the steps to be taken to make something happen, or how something is done. An example of a procedure is cracking eggs into a bowl and beating them before scrambling them in a pan.
What is procedure in PL SQL with example?
PL/SQL has two types of subprograms called procedures and functions. Generally, you use a procedure to perform an action and a function to compute a value. Like unnamed or anonymous PL/SQL blocks, subprograms have a declarative part, an executable part, and an optional exception-handling part.
Why do we use functions in PL SQL?
When a program calls a function, the program control is transferred to the called function. A called function performs the defined task and when its return statement is executed or when the last end statement is reached, it returns the program control back to the main program.
What is difference between function and stored procedure?
The function must return a value but in Stored Procedure it is optional. Even a procedure can return zero or n values. Functions can have only input parameters for it whereas Procedures can have input or output parameters. Functions can be called from Procedure whereas Procedures cannot be called from a Function.
What is the difference between procedure function and package in Oracle?
A package is a group of related procedures and functions, together with the cursors and variables they use, stored together in the database for continued use as a unit. Similar to standalone procedures and functions, packaged procedures and functions can be called explicitly by applications or users.
How many types of functions are there in Oracle?
There are two types of functions in Oracle. 1) Single Row Functions: Single row or Scalar functions return a value for every row that is processed in a query. 2) Group Functions: These functions group the rows of data based on the values returned by the query.
What is procedure and example?
The definition of procedure is order of the steps to be taken to make something happen, or how something is done. An example of a procedure is cracking eggs into a bowl and beating them before scrambling them in a pan.
What is a PL/SQL subprogram?
PL/SQL subprograms are named PL/SQL blocks that can be invoked with a set of parameters. PL/SQL provides two kinds of subprograms −
What is a subprogram in PL/SQL?
In this chapter, we will discuss Procedures in PL/SQL. A subprogram is a program unit/module that performs a particular task. These subprograms are combined to form larger programs. This is basically called the 'Modular design'. A subprogram can be invoked by another subprogram or program which is called the calling program.
What is an out parameter?
An OUT parameter returns a value to the calling program. Inside the subprogram, an OUT parameter acts like a variable. You can change its value and reference the value after assigning it. The actual parameter must be variable and it is passed by value.
Is the declaration part of a subprogram optional?
It is an optional part. However, the declarative part for a subprogram does not start with the DECLARE keyword. It contains declarations of types, cursors, constants, variables, exceptions, and nested subprograms. These items are local to the subprogram and cease to exist when the subprogram completes execution.
Is an IN parameter read only?
It is a read-only parameter. Inside the subprogram, an IN parameter acts like a constant. It cannot be assigned a value. You can pass a constant, literal, initialized variable, or expression as an IN parameter. You can also initialize it to a default value; however, in that case, it is omitted from the subprogram call.
Can you mix two notations in a procedure call?
In mixed notation , you can mix both notations in procedure call; however, the positional notation should precede the named notation.
Is an actual parameter a constant?
The actual parameter corresponding to an IN OUT formal parameter must be a variable, not a constant or an expression. Formal parameter must be assigned a value. Actual parameter is passed by value.
What is a procedure in SQL?
Answer: A procedure or function is a collection of PL/SQL and SQL statements that can execute a specific task. A procedure can do an action and not compulsorily return a value. But a function will return a value every time.
What is a function in PL/SQL?
The functions are similar to procedures in PL/SQL except for the fact that it has the ability to return a value (specified with keyword RETURN) and performs computation tasks. It has a unique name and acts as an independent block of code.
What is an out parameter?
This parameter return values to the calling subprogram. It is treated as a variable within a subprogram implying that it can be used as a local variable. OUT parameter value can be modified and referenced. An actual parameter must be a variable and always passed by value. It is a read-write variable within a subprogram.
What is a subprogram in SQL?
A subprogram can be built inside a package, within a block of PL/SQL or in a schema. A schema level subprogram is an independent one that mainly deals with the CREATE function or procedure. It is stored in the database and we can perform delete or drop operations on them.
What is the parameter set?
The parameter set defines the types, modes, and nature of the parameters. OUT parameter type points to the value that shall be returned outside the procedure. IN parameter type points to the value that shall be passed from outside.
Why is modularity important in programming?
It gives modularity to the code which means we can separate our program as per modules or clusters. It gives easy maintainability and scalability to the code. It gives the reusability of the code. It also helps to achieve abstraction in the code.
What do you need to call a function in a PL/SQL block?
Answer: For calling functions or procedures in a PL/SQL block, we need to mention the name, the parameters, BEGIN- END code, and exceptions if any, of the procedures or the function.
What is PL/SQL procedure?
The PL/SQL procedure is basic building block which is used to perform any action.
What is PL SQL?
The PL SQL functions are nothing but the named PL/SQL blocks which will used to return the specified value. The functions always returns the value.
What are procedures with real life example?
I have already given the details about the procedure and execution of the procedure. In this section I just want to throw light on what is mean by procedure.
What are the different types of functions in SQL?
There are two types of PL SQL functions : 1 In Built functions : These are built in functions by Oracle SQL or PL SQL engine. 2 User Defined Functions : These are basic building blocks which will return the value created by developers.
What are the three types of parameters in PLSQL?
There are three types of parameters which you can use to call the procedures in PLSQL i.e. IN,OUT,INOUT
Can you create a function to return the salary of an employee?
You can create a function to return the salary of employee.
Can you call a function as an expression?
You can call the function as expression or it is used to provide the parameter value .
What is the difference between a function and a procedure?
Used mainly to perform some computational process and returning the result of that process. Procedure can return zero or more values as output. Function can call with select statement , if function doesnot contain any DML statements and DDL statements..
What is a Pragma transaction?
Pragma transactions are the child transactions for the main transaction.
Can a function return only one value?
Function can return only single value as output. 3. Procedure cannot call with select statement, but can call from a block or from a procedure. Function can call with select statement , if function doesnot contain any DML statements and DDL statements..
Do you need pragma in a function?
No need of pragma declaration in a function with DML statement execution, when we are calling from PL-SQL block without select statement.
What is a PL/SQL stored procedure?
The PL/SQL stored procedure or simply a procedure is a PL/SQL block which performs one or more specific tasks. It is just like procedures in other programming languages. The procedure contains a header and a body. Header: The header contains the name of the procedure and the parameters or variables passed to the procedure.
How to pass parameters in a procedure?
How to pass parameters in procedure: When you want to create a procedure or function, you have to define parameters .There is three ways to pass parameters in procedure: IN parameters: The IN parameter can be referenced by the procedure or function. The value of the parameter cannot be overwritten by the procedure or the function.
What is the header in SQL?
Header: The header contains the name of the procedure and the parameters or variables passed to the procedure. Body: The body contains a declaration section, execution section and exception section similar to a general PL/SQL block.
What is a function in SQL?
A function can be used as a part of SQL expression i.e. we can use them with select/update/merge commands. One most important characteristic of a function is that unlike procedures, it must return a value.
Why do we make a single call to the database to run a block of statements?
We can make a single call to the database to run a block of statements thus it improves the performance against running SQL multiple times. This will reduce the number of calls between the database and the application.
Is PL/SQL secure?
It is secure since the code stays inside the database thus hiding internal database details from the application (user). The user only makes a call to the PL/SQL function s. Hence security and data hiding is ensured.
What is a function in a program?
A called function performs the defined task and when its return statement is executed or when the last end statement is reached, it returns the program control back to the main program.
How to use a function?
While creating a function, you give a definition of what the function has to do. To use a function, you will have to call that function to perform the defined task. When a program calls a function, the program control is transferred to the called function.
Is a function the same as a procedure?
A function is same as a procedure except that it returns a value. Therefore, all the discussions of the previous chapter are true for functions too.
Terminologies in PL/SQL Subprograms
Similarities Between Procedure and Function
- Both can be called from other PL/SQL blocks.
- If the exception raised in the subprogram is not handled in the subprogram exception handling section, then it will propagate to the calling block.
- Both can have as many parameters as required.
- Both are treated as database objects in PL/SQL.
Built-In Functions in PL/SQL
- PL/SQL contains various built-in functions to work with strings and date datatype. Here we are going to see the commonly used functions and their usage.
Summary
- In this chapter, we have learned the following. 1. How to create Procedure and different ways of calling it 2. How to create Function and different ways of calling it 3. Similarities and differences between Procedure and Function 4. Parameters and RETURN common terminologies in PL/SQL subprograms 5. Common built-in functions in Oracle PL/SQL
Parts of A PL/SQL Subprogram
- Each PL/SQL subprogram has a name, and may also have a parameter list. Like anonymous PL/SQL blocks, the named blocks will also have the following three parts −
Creating A Procedure
- A procedure is created with the CREATE OR REPLACE PROCEDUREstatement. The simplified syntax for the CREATE OR REPLACE PROCEDURE statement is as follows − Where, 1. procedure-namespecifies the name of the procedure. 2. [OR REPLACE] option allows the modification of an existing procedure. 3. The optional parameter list contains name, mode and types o...
Executing A Standalone Procedure
- A standalone procedure can be called in two ways − 1. Using the EXECUTEkeyword 2. Calling the name of the procedure from a PL/SQL block The above procedure named 'greetings'can be called with the EXECUTE keyword as − The above call will display − The procedure can also be called from another PL/SQL block − The above call will display −
Deleting A Standalone Procedure
- A standalone procedure is deleted with the DROP PROCEDUREstatement. Syntax for deleting a procedure is − You can drop the greetings procedure by using the following statement −
Methods For Passing Parameters
- Actual parameters can be passed in three ways − 1. Positional notation 2. Named notation 3. Mixed notation