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CREATE PROCEDURE (Transact-SQL)

  • Artykuł

Creates a Transact-SQL or common language runtime (CLR) stored procedure in SQL Server 2012. Stored procedures are similar to procedures in other programming languages in that they can:

  • Accept input parameters and return multiple values in the form of output parameters to the calling procedure or batch.

  • Contain programming statements that perform operations in the database, including calling other procedures.

  • Return a status value to a calling procedure or batch to indicate success or failure (and the reason for failure).

Use this statement to create a permanent procedure in the current database or a temporary procedure in the tempdb database.

Ikona łącza do tematu Transact-SQL Syntax Conventions

Składnia

--Transact-SQL Stored Procedure Syntax
CREATE { PROC | PROCEDURE } [schema_name.] procedure_name [ ; number ] 
    [ { @parameter [ type_schema_name. ] data_type }
        [ VARYING ] [ = default ] [ OUT | OUTPUT | [READONLY]
    ] [ ,...n ]
[ WITH <procedure_option> [ ,...n ] ]
[ FOR REPLICATION ]
AS { [ BEGIN ] sql_statement [;] [ ...n ] [ END ] }
[;]

<procedure_option> ::= 
    [ ENCRYPTION ]
    [ RECOMPILE ]
    [ EXECUTE AS Clause ]

--CLR Stored Procedure Syntax
CREATE { PROC | PROCEDURE } [schema_name.] procedure_name [ ; number ] 
    [ { @parameter [ type_schema_name. ] data_type } 
        [ = default ] [ OUT | OUTPUT ] [READONLY]
    ] [ ,...n ] 
[ WITH EXECUTE AS Clause ]
AS { EXTERNAL NAME assembly_name.class_name.method_name }
[;]

Arguments

  • schema_name
    The name of the schema to which the procedure belongs. Procedures are schema-bound. If a schema name is not specified when the procedure is created, the default schema of the user who is creating the procedure is automatically assigned.

  • procedure_name
    The name of the procedure. Procedure names must comply with the rules for identifiers and must be unique within the schema.

    Avoid the use of the sp_ prefix when naming procedures. This prefix is used by SQL Server to designate system procedures. Using the prefix can cause application code to break if there is a system procedure with the same name.

    Local or global temporary procedures can be created by using one number sign (#) before procedure_name (#procedure_name) for local temporary procedures, and two number signs for global temporary procedures (##procedure_name). A local temporary procedure is visible only to the connection that created it and is dropped when that connection is closed. A global temporary procedure is available to all connections and is dropped at the end of the last session using the procedure. Temporary names cannot be specified for CLR procedures.

    The complete name for a procedure or a global temporary procedure, including ##, cannot exceed 128 characters. The complete name for a local temporary procedure, including #, cannot exceed 116 characters.

  • ; number
    An optional integer that is used to group procedures of the same name. These grouped procedures can be dropped together by using one DROP PROCEDURE statement.

    [!UWAGA]

    This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.

    Numbered procedures cannot use the xml or CLR user-defined types and cannot be used in a plan guide.

  • @ parameter
    A parameter declared in the procedure. Specify a parameter name by using the at sign (@) as the first character. The parameter name must comply with the rules for identifiers. Parameters are local to the procedure; the same parameter names can be used in other procedures.

    One or more parameters can be declared; the maximum is 2,100. The value of each declared parameter must be supplied by the user when the procedure is called unless a default value for the parameter is defined or the value is set to equal another parameter. If a procedure contains table-valued parameters, and the parameter is missing in the call, an empty table is passed in. Parameters can take the place only of constant expressions; they cannot be used instead of table names, column names, or the names of other database objects. For more information, see EXECUTE (Transact-SQL).

    Parameters cannot be declared if FOR REPLICATION is specified.

  • [ type_schema_name**.** ] data_type
    The data type of the parameter and the schema to which the data type belongs.

    Guidelines for Transact-SQL procedures:

    • All Transact-SQL data types can be used as parameters.

    • You can use the user-defined table type to create table-valued parameters. Table-valued parameters can only be INPUT parameters and must be accompanied by the READONLY keyword. For more information, see Use Table-Valued Parameters (Database Engine)

    • cursor data types can only be OUTPUT parameters and must be accompanied by the VARYING keyword.

    Guidelines for CLR procedures:

    • All of the native SQL Server data types that have an equivalent in managed code can be used as parameters. For more information about the correspondence between CLR types and SQL Server system data types, see SQL Data Types and Their .NET Equivalents. For more information about SQL Server system data types and their syntax, see Data Types (Transact-SQL).

    • Table-valued or cursor data types cannot be used as parameters.

    • If the data type of the parameter is a CLR user-defined type, you must have EXECUTE permission on the type.

  • VARYING
    Specifies the result set supported as an output parameter. This parameter is dynamically constructed by the procedure and its contents may vary. Applies only to cursor parameters. This option is not valid for CLR procedures.

  • default
    A default value for a parameter. If a default value is defined for a parameter, the procedure can be executed without specifying a value for that parameter. The default value must be a constant or it can be NULL. The constant value can be in the form of a wildcard, making it possible to use the LIKE keyword when passing the parameter into the procedure. See Example C below.

    Default values are recorded in the sys.parameters.default column only for CLR procedures. That column will be NULL for Transact-SQL procedure parameters.

  • OUT | OUTPUT
    Indicates that the parameter is an output parameter. Use OUTPUT parameters to return values to the caller of the procedure. text, ntext, and image parameters cannot be used as OUTPUT parameters, unless the procedure is a CLR procedure. An output parameter can be a cursor placeholder, unless the procedure is a CLR procedure. A table-value data type cannot be specified as an OUTPUT parameter of a procedure.

  • READONLY
    Indicates that the parameter cannot be updated or modified within the body of the procedure. If the parameter type is a table-value type, READONLY must be specified.

  • RECOMPILE
    Indicates that the Database Engine does not cache a query plan for this procedure, forcing it to be compiled each time it is executed. For more information regarding the reasons for forcing a recompile, see Recompile a Stored Procedure. This option cannot be used when FOR REPLICATION is specified or for CLR procedures.

    To instruct the Database Engine to discard query plans for individual queries inside a procedure, use the RECOMPILE query hint in the definition of the query. For more information, see Query Hints (Transact-SQL).

  • ENCRYPTION
    Indicates that SQL Server will convert the original text of the CREATE PROCEDURE statement to an obfuscated format. The output of the obfuscation is not directly visible in any of the catalog views in SQL Server. Users who have no access to system tables or database files cannot retrieve the obfuscated text. However, the text will be available to privileged users who can either access system tables over the DAC port or directly access database files. Also, users who can attach a debugger to the server process can retrieve the decrypted procedure from memory at runtime. For more information about accessing system metadata, see Metadata Visibility Configuration.

    This option is not valid for CLR procedures.

    Procedures created with this option cannot be published as part of SQL Server replication.

  • EXECUTE AS
    Specifies the security context under which to execute the procedure.

    For more information, see EXECUTE AS Clause (Transact-SQL).

  • FOR REPLICATION
    Specifies that the procedure is created for replication. Consequently, it cannot be executed on the Subscriber. A procedure created with the FOR REPLICATION option is used as a procedure filter and is executed only during replication. Parameters cannot be declared if FOR REPLICATION is specified. FOR REPLICATION cannot be specified for CLR procedures. The RECOMPILE option is ignored for procedures created with FOR REPLICATION.

    A FOR REPLICATION procedure will have an object type RF in sys.objects and sys.procedures.

  • { [ BEGIN ] sql_statement [;] [ ...n ] [ END ] }
    One or more Transact-SQL statements comprising the body of the procedure. You can use the optional BEGIN and END keywords to enclose the statements. For information, see the Best Practices, General Remarks, and Limitations and Restrictions sections that follow.

  • EXTERNAL NAME assembly_name**.class_name.method_name
    Specifies the method of a .NET Framework assembly for a CLR procedure to reference. class_name must be a valid SQL Server identifier and must exist as a class in the assembly. If the class has a namespace-qualified name that uses a period (    .) to separate namespace parts, the class name must be delimited by using brackets ([** ]) or quotation marks (" "). The specified method must be a static method of the class.

    By default, SQL Server cannot execute CLR code. You can create, modify, and drop database objects that reference common language runtime modules; however, you cannot execute these references in SQL Server until you enable the clr enabled option. To enable the option, use sp_configure.

    [!UWAGA]

    CLR procedures are not supported in a contained database.

Best Practices

Although this is not an exhaustive list of best practices, these suggestions may improve procedure performance.

  • Use the SET NOCOUNT ON statement as the first statement in the body of the procedure. That is, place it just after the AS keyword. This turns off messages that SQL Server sends back to the client after any SELECT, INSERT, UPDATE, MERGE, and DELETE statements are executed. Overall performance of the database and application is improved by eliminating this unnecessary network overhead. For information, see SET NOCOUNT (Transact-SQL).

  • Use schema names when creating or referencing database objects in the procedure. It will take less processing time for the Database Engine to resolve object names if it does not have to search multiple schemas. It will also prevent permission and access problems caused by a user’s default schema being assigned when objects are created without specifying the schema.

  • Avoid wrapping functions around columns specified in the WHERE and JOIN clauses. Doing so makes the columns non-deterministic and prevents the query processor from using indexes.

  • Avoid using scalar functions in SELECT statements that return many rows of data. Because the scalar function must be applied to every row, the resulting behavior is like row-based processing and degrades performance.

  • Avoid the use of SELECT *. Instead, specify the required column names. This can prevent some Database Engine errors that stop procedure execution. For example, a SELECT * statement that returns data from a 12 column table and then inserts that data into a 12 column temporary table will succeed until the number or order of columns in either table is changed.

  • Avoid processing or returning too much data. Narrow the results as early as possible in the procedure code so that any subsequent operations performed by the procedure are done using the smallest data set possible. Send just the essential data to the client application. It is more efficient than sending extra data across the network and forcing the client application to work through unnecessarily large result sets.

  • Use explicit transactions by using BEGIN/END TRANSACTION and keep transactions as short as possible. Longer transactions mean longer record locking and a greater potential for deadlocking.

  • Use the Transact-SQL TRY…CATCH feature for error handling inside a procedure. TRY…CATCH can encapsulate an entire block of Transact-SQL statements. This not only creates less performance overhead, it also makes error reporting more accurate with significantly less programming.

  • Use the DEFAULT keyword on all table columns that are referenced by CREATE TABLE or ALTER TABLE Transact-SQL statements in the body of the procedure. This will prevent passing NULL to columns that do not allow null values.

  • Use NULL or NOT NULL for each column in a temporary table. The ANSI_DFLT_ON and ANSI_DFLT_OFF options control the way the Database Engine assigns the NULL or NOT NULL attributes to columns when these attributes are not specified in a CREATE TABLE or ALTER TABLE statement. If a connection executes a procedure with different settings for these options than the connection that created the procedure, the columns of the table created for the second connection can have different nullability and exhibit different behavior. If NULL or NOT NULL is explicitly stated for each column, the temporary tables are created by using the same nullability for all connections that execute the procedure.

  • Use modification statements that convert nulls and include logic that eliminates rows with null values from queries. Be aware that in Transact-SQL, NULL is not an empty or “nothing” value. It is a placeholder for an unknown value and can cause unexpected behavior, especially when querying for result sets or using AGGREGATE functions.

  • Use the UNION ALL operator instead of the UNION or OR operators, unless there is a specific need for distinct values. The UNION ALL operator requires less processing overhead because duplicates are not filtered out of the result set.

General Remarks

There is no predefined maximum size of a procedure.

Variables specified in the procedure can be user-defined or system variables, such as @@SPID.

When a procedure is executed for the first time, it is compiled to determine an optimal access plan to retrieve the data. Subsequent executions of the procedure may reuse the plan already generated if it still remains in the plan cache of the Database Engine.

One or more procedures can execute automatically when SQL Server starts. The procedures must be created by the system administrator in the master database and executed under the sysadmin fixed server role as a background process. The procedures cannot have any input or output parameters. For more information, see Execute a Stored Procedure.

Procedures are nested when one procedure call another or executes managed code by referencing a CLR routine, type, or aggregate. Procedures and managed code references can be nested up to 32 levels. The nesting level increases by one when the called procedure or managed code reference begins execution and decreases by one when the called procedure or managed code reference completes execution. Methods invoked from within the managed code do not count against the nesting level limit. However, when a CLR stored procedure performs data access operations through the SQL Server managed provider, an additional nesting level is added in the transition from managed code to SQL.

Attempting to exceed the maximum nesting level causes the entire calling chain to fail. You can use the @@NESTLEVEL function to return the nesting level of the current stored procedure execution.

Interoperability

The Database Engine saves the settings of both SET QUOTED_IDENTIFIER and SET ANSI_NULLS when a Transact-SQL procedure is created or modified. These original settings are used when the procedure is executed. Therefore, any client session settings for SET QUOTED_IDENTIFIER and SET ANSI_NULLS are ignored when the procedure is running.

Other SET options, such as SET ARITHABORT, SET ANSI_WARNINGS, or SET ANSI_PADDINGS are not saved when a procedure is created or modified. If the logic of the procedure depends on a particular setting, include a SET statement at the start of the procedure to guarantee the appropriate setting. When a SET statement is executed from a procedure, the setting remains in effect only until the procedure has finished running. The setting is then restored to the value the procedure had when it was called. This enables individual clients to set the options they want without affecting the logic of the procedure.

Any SET statement can be specified inside a procedure, except SET SHOWPLAN_TEXT and SET SHOWPLAN_ALL. These must be the only statements in the batch. The SET option chosen remains in effect during the execution of the procedure and then reverts to its former setting.

[!UWAGA]

SET ANSI_WARNINGS is not honored when passing parameters in a procedure, user-defined function, or when declaring and setting variables in a batch statement. For example, if a variable is defined as char(3), and then set to a value larger than three characters, the data is truncated to the defined size and the INSERT or UPDATE statement succeeds.

Limitations and Restrictions

The CREATE PROCEDURE statement cannot be combined with other Transact-SQL statements in a single batch.

The following statements cannot be used anywhere in the body of a stored procedure.

CREATE AGGREGATE

CREATE SCHEMA

SET SHOWPLAN_TEXT

CREATE DEFAULT

CREATE or ALTER TRIGGER

SET SHOWPLAN_XML

CREATE or ALTER FUNCTION

CREATE or ALTER VIEW

USE database_name

CREATE or ALTER PROCEDURE

SET PARSEONLY

CREATE RULE

SET SHOWPLAN_ALL

A procedure can reference tables that do not yet exist. At creation time, only syntax checking is performed. The procedure is not compiled until it is executed for the first time. Only during compilation are all objects referenced in the procedure resolved. Therefore, a syntactically correct procedure that references tables that do not exist can be created successfully; however, the procedure will fail at execution time if the referenced tables do not exist.

You cannot specify a function name as a parameter default value or as the value passed to a parameter when executing a procedure. However, you can pass a function as a variable as shown in the following example.

-- Passing the function value as a variable.
DECLARE @CheckDate datetime = GETDATE();
EXEC dbo.uspGetWhereUsedProductID 819, @CheckDate; 
GO

If the procedure makes changes on a remote instance of SQL Server, the changes cannot be rolled back. Remote procedures do not take part in transactions.

For the Database Engine to reference the correct method when it is overloaded in the .NET Framework, the method specified in the EXTERNAL NAME clause must have the following characteristics:

  • Be declared as a static method.

  • Receive the same number of parameters as the number of parameters of the procedure.

  • Use parameter types that are compatible with the data types of the corresponding parameters of the SQL Server procedure. For information about matching SQL Server data types to the .NET Framework data types, see SQL Data Types and Their .NET Equivalents.

Metadata

The following table lists the catalog views and dynamic management views that you can use to return information about stored procedures.

View

Description

sys.sql_modules

Returns the definition of a Transact-SQL procedure. The text of a procedure created with the ENCRYPTION option cannot be viewed by using the sys.sql_modules catalog view.

sys.assembly_modules

Returns information about a CLR procedure.

sys.parameters

Returns information about the parameters that are defined in a procedure

sys.sql_expression_dependencies sys.dm_sql_referenced_entities sys.dm_sql_referencing_entities

Returns the objects that are referenced by a procedure.

To estimate the size of a compiled procedure, use the following Performance Monitor Counters.

Performance Monitor object name

Performance Monitor Counter name

SQLServer: Plan Cache Object

Cache Hit Ratio

 

Cache Pages

 

Cache Object Counts*

*These counters are available for various categories of cache objects including ad hoc Transact-SQL, prepared Transact-SQL, procedures, triggers, and so on. For more information, see SQL Server, Plan Cache Object.

Security

Permissions

Requires CREATE PROCEDURE permission in the database and ALTER permission on the schema in which the procedure is being created, or requires membership in the db_ddladmin fixed database role.

For CLR stored procedures, requires ownership of the assembly referenced in the EXTERNAL NAME clause, or REFERENCES permission on that assembly.

Examples

Category

Featured syntax elements

Basic Syntax

CREATE PROCEDURE

Passing parameters

@parameter • = default • OUTPUT • table-valued parameter type • CURSOR VARYING

Modifying data by using a stored procedure

UPDATE

Error Handling

TRY…CATCH

Obfuscating the procedure definition

WITH ENCRYPTION

Forcing the Procedure to Recompile

WITH RECOMPILE

Setting the Security Context

EXECUTE AS

Basic Syntax

Examples in this section demonstrate the basic functionality of the CREATE PROCEDURE statement using the minimum required syntax.

A. Creating a simple Transact-SQL procedure

The following example creates a stored procedure that returns all employees (first and last names supplied), their job titles, and their department names from a view. This procedure does not use any parameters. The example then demonstrates three methods of executing the procedure.

USE AdventureWorks2012;
GO
IF OBJECT_ID ( 'HumanResources.uspGetAllEmployees', 'P' ) IS NOT NULL 
    DROP PROCEDURE HumanResources.uspGetAllEmployees;
GO
CREATE PROCEDURE HumanResources.uspGetAllEmployees
AS
    SET NOCOUNT ON;
    SELECT LastName, FirstName, Department
    FROM HumanResources.vEmployeeDepartmentHistory;
GO

The uspGetEmployees procedure can be executed in the following ways:

EXECUTE HumanResources.uspGetAllEmployees;
GO
-- Or
EXEC HumanResources.uspGetAllEmployees;
GO
-- Or, if this procedure is the first statement within a batch:
HumanResources.uspGetAllEmployees;

B. Returning more than one result set

The following procedure returns two result sets.

USE AdventureWorks2012;
GO
CREATE PROCEDURE dbo.uspMultipleResults 
AS
SELECT TOP(10) BusinessEntityID, Lastname, FirstName FROM Person.Person;
SELECT TOP(10) CustomerID, AccountNumber FROM Sales.Customer;
GO

C. Creating a CLR stored procedure

The following example creates the GetPhotoFromDB procedure that references the GetPhotoFromDB method of the LargeObjectBinary class in the HandlingLOBUsingCLR assembly. Before the procedure is created, the HandlingLOBUsingCLR assembly is registered in the local database.

CREATE ASSEMBLY HandlingLOBUsingCLR
FROM '\\MachineName\HandlingLOBUsingCLR\bin\Debug\HandlingLOBUsingCLR.dll';
GO
CREATE PROCEDURE dbo.GetPhotoFromDB
(
    @ProductPhotoID int,
    @CurrentDirectory nvarchar(1024),
    @FileName nvarchar(1024)
)
AS EXTERNAL NAME HandlingLOBUsingCLR.LargeObjectBinary.GetPhotoFromDB;
GO

Passing Parameters

Examples in this section demonstrate how to use input and output parameters to pass values to and from a stored procedure.

A. Creating a procedure with input parameters

The following example creates a stored procedure that returns information for a specific employee by passing values for the employee's first name and last name. This procedure accepts only exact matches for the parameters passed.

USE AdventureWorks2012;
GO
IF OBJECT_ID ( 'HumanResources.uspGetEmployees', 'P' ) IS NOT NULL 
    DROP PROCEDURE HumanResources.uspGetEmployees;
GO
CREATE PROCEDURE HumanResources.uspGetEmployees 
    @LastName nvarchar(50), 
    @FirstName nvarchar(50) 
AS 

    SET NOCOUNT ON;
    SELECT FirstName, LastName, Department
    FROM HumanResources.vEmployeeDepartmentHistory
    WHERE FirstName = @FirstName AND LastName = @LastName;
GO

The uspGetEmployees procedure can be executed in the following ways:

EXECUTE HumanResources.uspGetEmployees N'Ackerman', N'Pilar';
-- Or
EXEC HumanResources.uspGetEmployees @LastName = N'Ackerman', @FirstName = N'Pilar';
GO
-- Or
EXECUTE HumanResources.uspGetEmployees @FirstName = N'Pilar', @LastName = N'Ackerman';
GO
-- Or, if this procedure is the first statement within a batch:
HumanResources.uspGetEmployees N'Ackerman', N'Pilar';

B. Using a procedure with wildcard parameters

The following example creates a stored procedure that returns information for employees by passing full or partial values for the employee's first name and last name. This procedure pattern matches the parameters passed or, if not supplied, uses the preset default (last names that start with the letter D).

USE AdventureWorks2012;
GO
IF OBJECT_ID ( 'HumanResources.uspGetEmployees2', 'P' ) IS NOT NULL 
    DROP PROCEDURE HumanResources.uspGetEmployees2;
GO
CREATE PROCEDURE HumanResources.uspGetEmployees2 
    @LastName nvarchar(50) = N'D%', 
    @FirstName nvarchar(50) = N'%'
AS 
    SET NOCOUNT ON;
    SELECT FirstName, LastName, Department
    FROM HumanResources.vEmployeeDepartmentHistory
    WHERE FirstName LIKE @FirstName AND LastName LIKE @LastName;
GO

The uspGetEmployees2 procedure can be executed in many combinations. Only a few possible combinations are shown here.

EXECUTE HumanResources.uspGetEmployees2;
-- Or
EXECUTE HumanResources.uspGetEmployees2 N'Wi%';
-- Or
EXECUTE HumanResources.uspGetEmployees2 @FirstName = N'%';
-- Or
EXECUTE HumanResources.uspGetEmployees2 N'[CK]ars[OE]n';
-- Or
EXECUTE HumanResources.uspGetEmployees2 N'Hesse', N'Stefen';
-- Or
EXECUTE HumanResources.uspGetEmployees2 N'H%', N'S%';

C. Using OUTPUT parameters

The following example creates the uspGetList procedure. This procedures returns a list of products that have prices that do not exceed a specified amount. The example shows using multiple SELECT statements and multiple OUTPUT parameters. OUTPUT parameters enable an external procedure, a batch, or more than one Transact-SQL statement to access a value set during the procedure execution.

USE AdventureWorks2012;
GO
IF OBJECT_ID ( 'Production.uspGetList', 'P' ) IS NOT NULL 
    DROP PROCEDURE Production.uspGetList;
GO
CREATE PROCEDURE Production.uspGetList @Product varchar(40) 
    , @MaxPrice money 
    , @ComparePrice money OUTPUT
    , @ListPrice money OUT
AS
    SET NOCOUNT ON;
    SELECT p.[Name] AS Product, p.ListPrice AS 'List Price'
    FROM Production.Product AS p
    JOIN Production.ProductSubcategory AS s 
      ON p.ProductSubcategoryID = s.ProductSubcategoryID
    WHERE s.[Name] LIKE @Product AND p.ListPrice < @MaxPrice;
-- Populate the output variable @ListPprice.
SET @ListPrice = (SELECT MAX(p.ListPrice)
        FROM Production.Product AS p
        JOIN  Production.ProductSubcategory AS s 
          ON p.ProductSubcategoryID = s.ProductSubcategoryID
        WHERE s.[Name] LIKE @Product AND p.ListPrice < @MaxPrice);
-- Populate the output variable @compareprice.
SET @ComparePrice = @MaxPrice;
GO

Execute uspGetList to return a list of Adventure Works products (Bikes) that cost less than $700. The OUTPUT parameters @Cost and @ComparePrices are used with control-of-flow language to return a message in the Messages window.

[!UWAGA]

The OUTPUT variable must be defined when the procedure is created and also when the variable is used. The parameter name and variable name do not have to match; however, the data type and parameter positioning must match, unless @ListPrice = variable is used.

DECLARE @ComparePrice money, @Cost money 
EXECUTE Production.uspGetList '%Bikes%', 700, 
    @ComparePrice OUT, 
    @Cost OUTPUT
IF @Cost <= @ComparePrice 
BEGIN
    PRINT 'These products can be purchased for less than 
    $'+RTRIM(CAST(@ComparePrice AS varchar(20)))+'.'
END
ELSE
    PRINT 'The prices for all products in this category exceed 
    $'+ RTRIM(CAST(@ComparePrice AS varchar(20)))+'.'

Here is the partial result set:

Product                     List Price

--------------------------  ----------

Road-750 Black, 58          539.99

Mountain-500 Silver, 40     564.99

Mountain-500 Silver, 42     564.99

...

Road-750 Black, 48          539.99

Road-750 Black, 52          539.99

(14 row(s) affected)

These items can be purchased for less than $700.00.

D. Using a Table-Valued Parameter

The following example uses a table-valued parameter type to insert multiple rows into a table. The example creates the parameter type, declares a table variable to reference it, fills the parameter list, and then passes the values to a stored procedure. The stored procedure uses the values to insert multiple rows into a table.

USE AdventureWorks2012;
GO

/* Create a table type. */
CREATE TYPE LocationTableType AS TABLE 
( LocationName VARCHAR(50)
, CostRate INT );
GO

/* Create a procedure to receive data for the table-valued parameter. */
CREATE PROCEDURE usp_InsertProductionLocation
    @TVP LocationTableType READONLY
    AS 
    SET NOCOUNT ON
    INSERT INTO [AdventureWorks2012].[Production].[Location]
           ([Name]
           ,[CostRate]
           ,[Availability]
           ,[ModifiedDate])
        SELECT *, 0, GETDATE()
        FROM  @TVP;
GO

/* Declare a variable that references the type. */
DECLARE @LocationTVP 
AS LocationTableType;

/* Add data to the table variable. */
INSERT INTO @LocationTVP (LocationName, CostRate)
    SELECT [Name], 0.00
    FROM 
    [AdventureWorks2012].[Person].[StateProvince];

/* Pass the table variable data to a stored procedure. */
EXEC usp_InsertProductionLocation @LocationTVP;
GO

E. Using an OUTPUT cursor parameter

The following example uses the OUTPUT cursor parameter to pass a cursor that is local to a procedure back to the calling batch, procedure, or trigger.

First, create the procedure that declares and then opens a cursor on the Currency table:

USE AdventureWorks2012;
GO
IF OBJECT_ID ( 'dbo.uspCurrencyCursor', 'P' ) IS NOT NULL
    DROP PROCEDURE dbo.uspCurrencyCursor;
GO
CREATE PROCEDURE dbo.uspCurrencyCursor 
    @CurrencyCursor CURSOR VARYING OUTPUT
AS
    SET NOCOUNT ON;
    SET @CurrencyCursor = CURSOR
    FORWARD_ONLY STATIC FOR
      SELECT CurrencyCode, Name
      FROM Sales.Currency;
    OPEN @CurrencyCursor;
GO

Next, run a batch that declares a local cursor variable, executes the procedure to assign the cursor to the local variable, and then fetches the rows from the cursor.

USE AdventureWorks2012;
GO
DECLARE @MyCursor CURSOR;
EXEC dbo.uspCurrencyCursor @CurrencyCursor = @MyCursor OUTPUT;
WHILE (@@FETCH_STATUS = 0)
BEGIN;
     FETCH NEXT FROM @MyCursor;
END;
CLOSE @MyCursor;
DEALLOCATE @MyCursor;
GO

Modifying Data by using a Stored Procedure

Examples in this section demonstrate how to insert or modify data in tables or views by including a Data Manipulation Language (DML) statement in the definition of the procedure.

A. Using UPDATE in a stored procedure

The following example uses an UPDATE statement in a stored procedure. The procedure takes one input parameter, @NewHours and one output parameter @RowCount. The @NewHours parameter value is used in the UPDATE statement to update the column VacationHours in the table HumanResources.Employee. The @RowCount output parameter is used to return the number of rows affected to a local variable. A CASE expression is used in the SET clause to conditionally determine the value that is set for VacationHours. When the employee is paid hourly (SalariedFlag = 0), VacationHours is set to the current number of hours plus the value specified in @NewHours; otherwise, VacationHours is set to the value specified in @NewHours.

USE AdventureWorks2012;
GO
CREATE PROCEDURE HumanResources.Update_VacationHours
@NewHours smallint
AS 
SET NOCOUNT ON;
UPDATE HumanResources.Employee
SET VacationHours = 
    ( CASE
         WHEN SalariedFlag = 0 THEN VacationHours + @NewHours
         ELSE @NewHours
       END
    )
WHERE CurrentFlag = 1;
GO

EXEC HumanResources.Update_VacationHours 40;

Error Handling

Examples in this section demonstrate methods to handle errors that might occur when the stored procedure is executed.

Using TRY…CATCH

The following example using the TRY…CATCH construct to return error information caught during the execution of a stored procedure.

USE AdventureWorks2012;
GO

CREATE PROCEDURE Production.uspDeleteWorkOrder ( @WorkOrderID int )
AS
SET NOCOUNT ON;
BEGIN TRY
   BEGIN TRANSACTION 
   -- Delete rows from the child table, WorkOrderRouting, for the specified work order.
   DELETE FROM Production.WorkOrderRouting
   WHERE WorkOrderID = @WorkOrderID;

   -- Delete the rows from the parent table, WorkOrder, for the specified work order.
   DELETE FROM Production.WorkOrder
   WHERE WorkOrderID = @WorkOrderID;
  
   COMMIT

END TRY
BEGIN CATCH
  -- Determine if an error occurred.
  IF @@TRANCOUNT > 0
     ROLLBACK

  -- Return the error information.
  DECLARE @ErrorMessage nvarchar(4000),  @ErrorSeverity int;
  SELECT @ErrorMessage = ERROR_MESSAGE(),@ErrorSeverity = ERROR_SEVERITY();
  RAISERROR(@ErrorMessage, @ErrorSeverity, 1);
END CATCH;

GO
EXEC Production.uspDeleteWorkOrder 13;

/* Intentionally generate an error by reversing the order in which rows are deleted from the
   parent and child tables. This change does not cause an error when the procedure
   definition is altered, but produces an error when the procedure is executed.
*/
ALTER PROCEDURE Production.uspDeleteWorkOrder ( @WorkOrderID int )
AS

BEGIN TRY
   BEGIN TRANSACTION 
      -- Delete the rows from the parent table, WorkOrder, for the specified work order.
   DELETE FROM Production.WorkOrder
   WHERE WorkOrderID = @WorkOrderID;
  
   -- Delete rows from the child table, WorkOrderRouting, for the specified work order.
   DELETE FROM Production.WorkOrderRouting
   WHERE WorkOrderID = @WorkOrderID;
  
   COMMIT TRANSACTION

END TRY
BEGIN CATCH
  -- Determine if an error occurred.
  IF @@TRANCOUNT > 0
     ROLLBACK TRANSACTION

  -- Return the error information.
  DECLARE @ErrorMessage nvarchar(4000),  @ErrorSeverity int;
  SELECT @ErrorMessage = ERROR_MESSAGE(),@ErrorSeverity = ERROR_SEVERITY();
  RAISERROR(@ErrorMessage, @ErrorSeverity, 1);
END CATCH;
GO
-- Execute the altered procedure.
EXEC Production.uspDeleteWorkOrder 15;

DROP PROCEDURE Production.uspDeleteWorkOrder;

Obfuscating the Procedure Definition

Examples in this section show how to obfuscate the definition of the stored procedure.

A. Using the WITH ENCRYPTION option

The following example creates the HumanResources.uspEncryptThis procedure.

USE AdventureWorks2012;
GO
IF OBJECT_ID ( 'HumanResources.uspEncryptThis', 'P' ) IS NOT NULL 
    DROP PROCEDURE HumanResources.uspEncryptThis;
GO
CREATE PROCEDURE HumanResources.uspEncryptThis
WITH ENCRYPTION
AS
    SET NOCOUNT ON;
    SELECT BusinessEntityID, JobTitle, NationalIDNumber, VacationHours, SickLeaveHours 
    FROM HumanResources.Employee;
GO

The WITH ENCRYPTION option obfuscates the definition of the procedure when querying the system catalog or using metadata functions, as shown by the following examples.

Run sp_helptext:

EXEC sp_helptext 'HumanResources.uspEncryptThis';

Here is the result set.

The text for object 'HumanResources.uspEncryptThis' is encrypted.

Directly query the sys.sql_modules catalog view:

USE AdventureWorks2012;
GO
SELECT definition FROM sys.sql_modules
WHERE object_id = OBJECT_ID('HumanResources.uspEncryptThis');

Here is the result set.

definition

--------------------------------

NULL

Forcing the Procedure to Recompile

Examples in this section use the WITH RECOMPILE clause to force the procedure to recompile every time it is executed.

A. Using the WITH RECOMPILE option

The WITH RECOMPILE clause is helpful when the parameters supplied to the procedure will not be typical, and when a new execution plan should not be cached or stored in memory.

USE AdventureWorks2012;
GO
IF OBJECT_ID ( 'dbo.uspProductByVendor', 'P' ) IS NOT NULL 
    DROP PROCEDURE dbo.uspProductByVendor;
GO
CREATE PROCEDURE dbo.uspProductByVendor @Name varchar(30) = '%'
WITH RECOMPILE
AS
    SET NOCOUNT ON;
    SELECT v.Name AS 'Vendor name', p.Name AS 'Product name'
    FROM Purchasing.Vendor AS v 
    JOIN Purchasing.ProductVendor AS pv 
      ON v.BusinessEntityID = pv.BusinessEntityID 
    JOIN Production.Product AS p 
      ON pv.ProductID = p.ProductID
    WHERE v.Name LIKE @Name;
GO

Setting the Security Context

Examples in this section use the EXECUTE AS clause to set the security context in which the stored procedure executes.

A. Using the EXECUTE AS clause

The following example shows using the EXECUTE AS clause to specify the security context in which a procedure can be executed. In the example, the option CALLER specifies that the procedure can be executed in the context of the user that calls it.

USE AdventureWorks2012;
GO
IF OBJECT_ID ( 'Purchasing.uspVendorAllInfo', 'P' ) IS NOT NULL 
    DROP PROCEDURE Purchasing.uspVendorAllInfo;
GO
CREATE PROCEDURE Purchasing.uspVendorAllInfo
WITH EXECUTE AS CALLER
AS
    SET NOCOUNT ON;
    SELECT v.Name AS Vendor, p.Name AS 'Product name', 
      v.CreditRating AS 'Rating', 
      v.ActiveFlag AS Availability
    FROM Purchasing.Vendor v 
    INNER JOIN Purchasing.ProductVendor pv
      ON v.BusinessEntityID = pv.BusinessEntityID 
    INNER JOIN Production.Product p
      ON pv.ProductID = p.ProductID 
    ORDER BY v.Name ASC;
GO

B. Creating custom permission sets

The following example uses EXECUTE AS to create custom permissions for a database operation. Some operations such as TRUNCATE TABLE, do not have grantable permissions. By incorporating the TRUNCATE TABLE statement within a stored procedure and specifying that procedure execute as a user that has permissions to modify the table, you can extend the permissions to truncate the table to the user that you grant EXECUTE permissions on the procedure.

CREATE PROCEDURE dbo.TruncateMyTable
WITH EXECUTE AS SELF
AS TRUNCATE TABLE MyDB..MyTable;

Zobacz także

Odwołanie

ALTER PROCEDURE (Transact-SQL)

Control-of-Flow Language (Transact-SQL)

Data Types (Transact-SQL)

DECLARE @local\_variable (Transact-SQL)

DROP PROCEDURE (Transact-SQL)

EXECUTE (Transact-SQL)

EXECUTE AS (Transact-SQL)

sp_procoption (Transact-SQL)

sp_recompile (Transact-SQL)

sys.sql_modules (Transact-SQL)

sys.parameters (Transact-SQL)

sys.procedures (Transact-SQL)

sys.sql_expression_dependencies (Transact-SQL)

sys.assembly_modules (Transact-SQL)

sys.numbered_procedures (Transact-SQL)

sys.numbered_procedure_parameters (Transact-SQL)

OBJECT_DEFINITION (Transact-SQL)

sys.dm_sql_referenced_entities (Transact-SQL)

sys.dm_sql_referencing_entities (Transact-SQL)

Koncepcje

Cursors

Stored Procedures (Database Engine)

Create a Stored Procedure

Use Table-Valued Parameters (Database Engine)