The purpose of creating a procedure is to help employees perform certain tasks. A procedure should specify the steps that should be performed to achieve a particular goal, including the parameters, the exit or output, and the reason for its implementation. Here are some tips for creating a procedure. Read on to learn how to create an effective one. Let's get started. In a brief introduction, you can describe the process and its objectives. It should be short enough to allow employees to understand its importance.
Specifies the steps to be taken
A procedure is a sequence of statements that are used to perform a certain task. A procedure definition string contains information that is specific to that procedure. A procedure definition string may be a name for an internal procedure, a path to an object file, or a SQL command. Procedure definitions may also include text written in procedural language. When writing a procedure, consider the level of detail that is required by the reader.
Specifies the parameters
A procedure uses parameters to provide input to the calling code. Parameters are defined the same way as variables are: with a name, data type, and passing mechanism. For example, a procedure to add two supplied integers requires two parameters, a starting value and a destination value. Parameters can be optional or required, and are declared in the procedure declaration. The definition is called a parameter list.
The parameter name can be an internal procedure name, the path to an object file, a SQL command, or any text written in procedural language. Specifying the name in single quotes is deprecated. Instead, use dollar quoting, which often makes more sense than normal single quotes. In addition, dollar quoting allows backslashes and single quotes to escape. These are the two most common types of parameters.
Procedures may take up to six parameters. The first three must be mandatory. The fourth parameter may be optional. If the parameter is optional, it should be preceded by 'optional' and then a single-quotation-mark. Specifying the parameters of procedures must be done in a way that allows the procedure to operate correctly. When parameter names have multiple quotation marks, they can be too long. Parameters that have more than one parameter will result in an error.
A procedure can specify parameters as input, output, or both. It can also specify whether to return the result. The output parameter is used in a separate calculation. The input parameter is also an input. The output parameter is the result of the calculation. Then the procedure returns at the end of its calculations. These are the two most common ways of specifying parameters. This allows a procedure to perform calculations without changing the original input values.
Another way to specify the parameters of a procedure is to declare it as an item. The item declaration acts as a hint to the compiler. It enables the PL/SQL compiler to pass parameters by reference. A formal parameter is a variable declared in the procedure spec and referenced in the procedure body. A procedure may also be declared as an autonomous transaction, which is a separate independent transaction that can suspend the main transaction while doing SQL operations. It can also rollback and commit its changes.
Specifies the exit
The CHECK statement, which is used at the start of a procedure, checks whether the execution of a certain statement is prerequisite to the statement. It has two uses. First, it checks whether the statement is valid and, second, it exits if a specific condition is not met. When used outside of a loop, it does not have any legibility implications. In addition, it can only be used to specify the exit from procedures if the expression is logical. To use it, you must make sure that it has a double negation.
Another use of Exit is to stop a procedure in its current subroutine. If it is invoked in the main program routine, it will stop the execution of the program. Specifying the exit value in a function is possible with the optional X argument. If the result of the function is X, then the function is terminated. You can also use an Exit statement with a Try.. Finally construct to execute a block of code.
The LOOP keyword starts a basic unconditional loop within a function. A loop's basic job is to execute all statements in the body until it encounters the EXIT keyword. For this reason, it is necessary to use the WHEN keyword, followed by an expression. If the expression evaluates to TRUE, then the statement will exit the loop and the control will return to the top of the loop. Otherwise, it will continue to loop until the condition is met.
Forced exits work by making a call to the Exit system service. In this way, the SYS$FORCEX service causes an Exit service call on behalf of the specified process. Then, it returns the target process's PID. The Force Exit system service requires system dynamic memory. The $FORCEX service has two types of arguments. The pidadr argument is optional, but must be specified if the target process is not a member of the same UIC group as the calling process.
Specifies the output
A procedure specifies the parameters it uses and outputs. The parameters are either primitive SQL types or table types. You specify the table type and programming language in the procedure signature. The default programming language is SQLSCRIPT. Other programming languages include GRAPH, a domain-specific language used for custom graph analytics and algorithms. Specify user privileges, if applicable. If the procedure needs to use an external routine, it must use the AS LOCATOR subclause to validate its output.