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SQL Anywhere 10.0.1 » SQL Anywhere Server - SQL Reference » SQL Statements

CREATE MESSAGE statement [T-SQL] Next Page

CREATE PROCEDURE statement

Use this statement to create a procedure in the database.

Syntax 1 - Creating user defined procedures

CREATE [ TEMPORARY ] PROCEDURE [ owner.]procedure-name ( [ parameter, ... ] )
{ [ RESULT ( result-column, ... ) | NO RESULT SET ]
[ ON EXCEPTION RESUME ]
compound-statement
| AT location-string
| EXTERNAL NAME library-call
| [ DYNAMIC RESULT SETS integer-expression ]
[ EXTERNAL NAME java-call LANGUAGE JAVA ]
}

parameter :
parameter-mode parameter-name data-type [ DEFAULT expression ]
| SQLCODE
| SQLSTATE

parameter-mode : IN | OUT | INOUT

result-column : column-name data-type

library-call :
[operating-system:]function-name@library; ...

operating-system : NetWare | Unix

java-call :
[package-name.]class-name.method-name method-signature

method-signature :
( [ field-descriptor, ... ] ) return-descriptor

field-descriptor | return-descriptor :
Z | B | S | I | J | F | D | C | V | [descriptor | Lclass-name;

Syntax 2 - Create web services

CREATE PROCEDURE [ owner.]procedure-name ( [ parameter, ... ] )
URL url-string
[ HEADER header-string ]
[ SOAPHEADER soap-header-string ]
[ TYPE { 'HTTP[ :{ GET | POST } ]' | 'SOAP[:{ RPC | DOC } ]' } ]
[ NAMESPACE namespace-string ]
[ CERTIFICATE certificate-string ]
[ CLIENTPORT clientport-string ]
[ PROXY proxy-string ]
[ SET protocol-option-string

parameter :
parameter-mode parameter-name data-type [ DEFAULT expression ]
| SQLCODE
| SQLSTATE

parameter-mode : IN | OUT | INOUT

url-string :
{ HTTP | HTTPS | HTTPS_FIPS }://[user:password@]hostname[:port][/path]

header-string :
The string to use for the HTTP header.

protocol-option-string
[ http-option-list]
[, soap-option-list ]

http-option-list :
HTTP (
[ CH[UNK]={ ON | OFF | AUTO } ]
[; VER[SION]={ 1.0 | 1.1 } ]
)

soap-option-list:
SOAP (
OP[ERATION]=soap-operation-name
)

soap-operation-name :
The name of the SOAP operation to call.

Parameters

CREATE PROCEDURE clause    You can create permanent or temporary (TEMPORARY) stored procedures. You can use PROC as a synonym for PROCEDURE.

Parameter names must conform to the rules for other database identifiers such as column names. They must be a valid SQL data type (see SQL Data Types). Parameters can be prefixed with one of the keywords IN, OUT, or INOUT. If you do not specify one of these values, parameters are INOUT by default. The keywords have the following meanings:

When procedures are executed using the CALL statement, not all parameters need to be specified. If a default value is provided in the CREATE PROCEDURE statement, missing parameters are assigned the default values. If an argument is not provided in the CALL statement, and no default is set, an error is given.

SQLSTATE and SQLCODE are special parameters that output the SQLSTATE or SQLCODE value when the procedure ends (they are OUT parameters). Whether or not a SQLSTATE and SQLCODE parameter is specified, the SQLSTATE and SQLCODE special values can always be checked immediately after a procedure call to test the return status of the procedure.

The SQLSTATE and SQLCODE special values are modified by the next SQL statement. Providing SQLSTATE or SQLCODE as procedure arguments allows the return code to be stored in a variable.

Specifying TEMPORARY (CREATE TEMPORARY PROCEDURE) means that the stored procedure is visible only by the connection that created it, and that it is automatically dropped when the connection is dropped. Temporary stored procedures can also be explicitly dropped. You cannot perform ALTER, GRANT, or REVOKE on them, and, unlike other stored procedures, temporary stored procedures are not recorded in the catalog or transaction log.

Temporary stored procedures execute with the permissions of their creator (current user), and can only be owned by their creator. Therefore, do not specify owner when creating a temporary stored procedure.

Temporary stored procedures can be created and dropped when connected to a read-only database, and they cannot be external procedures.

For example, the following temporary procedure drops the table called CustRank, if it exists. For this example, the procedure assumes that the table name is unique and can be referenced by the procedure creator without specifying the table owner:

CREATE TEMPORARY PROCEDURE drop_table( IN CustRank char(128) )
BEGIN
    IF EXISTS ( SELECT * FROM SYS.SYSTAB WHERE table_name = CustRank ) THEN
   EXECUTE IMMEDIATE 'DROP TABLE "' || CustRank || '"';
   MESSAGE 'Table "' || CustRank || '" dropped' to client;
    END IF;
END;

RESULT clause    The RESULT clause declares the number and type of columns in the result set. The parenthesized list following the RESULT keyword defines the result column names and types. This information is returned by the embedded SQL DESCRIBE or by ODBC SQLDescribeCol when a CALL statement is being described. Allowable data types are listed in SQL Data Types.

For more information on returning result sets from procedures, see Returning results from procedures.

Some procedures can produce more than one result set, with different numbers of columns, depending on how they are executed. For example, the following procedure returns two columns under some circumstances, and one in others.

CREATE PROCEDURE names( IN formal char(1))
BEGIN
   IF formal = 'n' THEN
      SELECT GivenName
      FROM Employees
   ELSE
      SELECT Surname, GivenName
      FROM Employees
   END IF
END;

Procedures with variable result sets must be written without a RESULT clause, or in Transact-SQL. Their use is subject to the following limitations:

If your procedure returns only one result set, you should use a RESULT clause. The presence of this clause prevents ODBC and Open Client applications from re-describing the result set after a cursor is open.

To handle multiple result sets, ODBC must describe the currently executing cursor, not the procedure's defined result set. Therefore, ODBC does not always describe column names as defined in the RESULT clause of the procedure definition. To avoid this problem, use column aliases in the SELECT statement that generates the result set.

NO RESULT SET clause    Declares that no result set is returned by this procedure. This is useful when an external environment needs to know that a procedure does not return a result set.

ON EXCEPTION RESUME clause    This clause enables Transact-SQL -like error handling to be used within a Watcom-SQL syntax procedure.

If you use ON EXCEPTION RESUME, the procedure takes an action that depends on the setting of the on_tsql_error option. If on_tsql_error is set to Conditional (which is the default) the execution continues if the next statement handles the error; otherwise, it exits.

Error-handling statements include the following:

You should not use explicit error handling code with an ON EXCEPTION RESUME clause.

See on_tsql_error option [compatibility].

AT location-string clause    Create a proxy stored procedure on the current database for a remote procedure specified by location-string. The AT clause supports the semicolon (;) as a field delimiter in location-string. If no semicolon is present, a period is the field delimiter. This allows file names and extensions to be used in the database and owner fields.

Remote procedures can return only up to 254 characters in output variables.

For information on remote servers, see CREATE SERVER statement. For information on using remote procedures, see Using remote procedure calls (RPCs).

EXTERNAL NAME clause    A procedure using the EXTERNAL NAME clause is a wrapper around a call to an external library. A stored procedure using EXTERNAL NAME can have no other clauses following the parameter list. The library name may include the file extension, which is typically .dll on Windows, .so on Unix, and .nlm on NetWare. In the absence of the extension, the software appends the platform-specific default file extension for libraries. On NetWare, if no NLM name is given, the NLM containing the symbol must already be loaded when the function is called.

For information about external library calls, see Calling external libraries from procedures.

DYNAMIC RESULT SETS clause    This clause is directly tied to the EXTERNAL NAME LANGUAGE JAVA clause, and is for use with procedures that are wrappers around Java methods. If the DYNAMIC RESULT SETS clause is not provided, it is assumed that the method returns no result set.

EXTERNAL NAME java-call LANGUAGE JAVA clause    A procedure that uses EXTERNAL NAME with a LANGUAGE JAVA clause is a wrapper around a Java method. A Java method signature is a compact character representation of the types of the parameters and the type of the return value. If the number of parameters is less than the number indicated in the method-signature then the difference must equal the number specified in DYNAMIC RESULT SETS, and each parameter in the method signature in excess of those in the procedure parameter list must have a method signature of [Ljava/SQL/ResultSet;.

The field-descriptor and return-descriptor have the following meanings:

Field type Java data type
B byte
C char
D double
F float
I int
J long
L class-name; an instance of the class class-name. The class name must be fully qualified, and any dot in the name must be replaced by a /. For example, java/lang/String
S short
V void
Z Boolean
[ use one for each dimension of an array

For example,

double some_method(
  boolean a,
  int b,
  java.math.BigDecimal c,
  byte [][] d,
  java.sql.ResultSet[] rs ) {
}

would have the following signature:

'(ZILjava/math/BigDecimal;[[B[Ljava/SQL/ResultSet;)D'

See Returning result sets from Java methods.

URL clause    For use only when defining an HTTP or SOAP web services client procedure. Specifies the URI of the web service. The optional user name and password parameters provide a means of supplying the credentials needed for HTTP basic authentication. HTTP basic authentication base-64 encodes the user and password information and passes it in the Authentication header of the HTTP request.

Specifying HTTPS_FIPS forces the system to use the FIPS libraries. If HTTPS_FIPS is specified, but no FIPS libraries are present, non-FIPS libraries are used instead.

When specified in this way, the user name and password are passed unencrypted, as part of the URL.

HEADER clause    When creating HTTP web service client procedures, use this clause to modify HTTP request header entries, add new ones, or suppress existing headers. The specification of headers closely resembles the format specified in RFC2616 Hypertext Transfer Protocol — HTTP/1.1, and RFC822 Standard for ARPA Internet Text Messages, including the fact that only printable ASCII characters can be specified for HTTP headers, and they are case-insensitive. Following are a few key points regarding HTTP header specification:

This example shows how to add static user-defined headers:

CREATE PROCEDURE http_client() URL 'http://localhost/getdata' 
  TYPE 'http:get' HEADER 'UserHeader1:value1\nUserHeader2:value2';

This example shows how to add new parameter-substituted user-defined headers:

CREATE PROCEDURE http_client( headers LONG VARCHAR ) URL 'http://localhost/getdata' 
TYPE 'http:get' HEADER '!headers';
CALL http_client( 'NewHeader1:value1\nNewHeader2:value2' );

For more information about using HTTP headers, see Working with HTTP headers.

SOAPHEADER clause    When declaring a SOAP web service as a procedure, use this clause to specify one or more SOAP request header entries. A SOAP header can be declared as a static constant, or can be dynamically set using the parameter substitution mechanism (declaring IN, OUT, or INOUT parameters for hd1, hd2, and so on). A web service procedure can define one or more IN mode substitution parameters, and a single INOUT or OUT substitution parameter.

The following example illustrates how a client can specify the sending of several header entries with parameters and receiving the response SOAP header data:

CREATE PROCEDURE soap_client( INOUT VARCHAR hd1, IN VARCHAR hd2, IN VARCHAR hd3 ) 
  URL 'localhost/some_endpoint' 
  SOAPHEADER '!hd1!hd2!hd3';

For more information on using SOAP headers, see Working with SOAP headers.

TYPE clause    Used to specify the format used when making the web service request. If SOAP is specified or no type clause is included, the default type SOAP:RPC is used. HTTP implies HTTP:POST. Since SOAP requests are always sent as XML documents, HTTP:POST is always used to send SOAP requests.

NAMESPACE clause    Applies to SOAP client procedures only. This clause identifies the method namespace usually required for both SOAP:RPC and SOAP:DOC requests. The SOAP server handling the request uses this namespace to interpret the names of the entities in the SOAP request message body. The namespace can be obtained from the WSDL description of the SOAP service available from the web service server. The default value is the procedure's URL, up to but not including the optional path component.

CERTIFICATE clause    To make a secure (HTTPS) request, a client must have access to the certificate used by the HTTPS server. The necessary information is specified in a string of semicolon-separated key/value pairs. The certificate can be placed in a file and the name of the file provided using the file key, or the whole certificate can be placed in a string, but not both. The following keys are available:

KeyAbbreviationDescription
fileThe file name of the certificate.
certificatecertThe certificate itself.
companycoThe company specified in the certificate.
unitThe company unit specified in the certificate.
nameThe common name specified in the certificate.

Certificates are required only for requests that are either directed to an HTTPS server, or can be redirected from a non-secure to a secure server.

CLIENTPORT clause    Identifies the port number on which the HTTP client procedure communicates using TCP/IP. It is provided for and recommended only for connections across firewalls, as firewalls filter according to the TCP/UDP port. You can specify a single port number, ranges of port numbers, or a combination of both; for example, CLIENTPORT '85,90-97'.

See ClientPort protocol option [CPORT].

PROXY clause    Specifies the URI of a proxy server. For use when the client must access the network through a proxy. Indicates that the procedure is to connect to the proxy server and send the request to the web service through it.

SET clause    Specifies protocol-specific behavior options for HTTP and SOAP. The following list describes the supported SET options. CHUNK and VERSION apply to the HTTP protocol, and OPERATION applies to the SOAP protocol. Parameter substitution is supported for this clause.

The following statement shows how several protocol-option settings are combined in the same SET clause:

CREATE PROCEDURE accounts_login( 
      name LONG VARCHAR, 
      pwd LONG VARCHAR )
   SET 'HTTP ( CHUNK=ON; VERSION=1.1 ), SOAP( OPERATION=login )' 
   ...

For more information on creating web services, including examples, see SQL Anywhere Web Services.

Remarks

The CREATE PROCEDURE statement creates a procedure in the database. Users with DBA authority can create procedures for other users by specifying an owner. A procedure is invoked with a CALL statement.

If a stored procedure returns a result set, it cannot also set output parameters or return a return value.

For web service client procedures, parameter values are passed as part of the request. The syntax used depends on the type of request. For HTTP:GET, the parameters are passed as part of the URL; for HTTP:POST requests, the values are placed in the body of the request. Parameters to SOAP requests are always bundled in the request body.

Permissions

Must have RESOURCE authority, unless creating a temporary procedure.

Must have DBA authority for external procedures or to create a procedure for another user.

Side effects

Automatic commit.

See also
Standards and compatibility
Examples

The following procedure uses a case statement to classify the results of a query.

CREATE PROCEDURE ProductType (IN product_ID INT, OUT type CHAR(10))
BEGIN
   DECLARE prod_name CHAR(20);
   SELECT name INTO prod_name FROM Products
   WHERE ID = product_ID;
   CASE prod_name
   WHEN 'Tee Shirt' THEN
      SET type = 'Shirt'
   WHEN 'Sweatshirt' THEN
      SET type = 'Shirt'
   WHEN 'Baseball Cap' THEN
      SET type = 'Hat'
   WHEN 'Visor' THEN
      SET type = 'Hat'
   WHEN 'Shorts' THEN
      SET type = 'Shorts'
   ELSE
      SET type = 'UNKNOWN'
   END CASE;
END;

The following procedure uses a cursor and loops over the rows of the cursor to return a single value.

CREATE PROCEDURE TopCustomer (OUT TopCompany CHAR(35), OUT TopValue INT)
BEGIN
   DECLARE err_notfound EXCEPTION
   FOR SQLSTATE '02000';
   DECLARE curThisCust CURSOR FOR
      SELECT CompanyName,
          CAST(SUM(SalesOrderItems.Quantity *
          Products.UnitPrice) AS INTEGER) VALUE
      FROM Customers
      LEFT OUTER JOIN SalesOrders
      LEFT OUTER JOIN SalesOrderItems
      LEFT OUTER JOIN Products
      GROUP BY CompanyName;
   DECLARE ThisValue INT;
   DECLARE ThisCompany CHAR(35);
   SET TopValue = 0;
   OPEN curThisCust;
   CustomerLoop:
   LOOP
      FETCH NEXT curThisCust
      INTO ThisCompany, ThisValue;
      IF SQLSTATE = err_notfound THEN
         LEAVE CustomerLoop;
      END IF;
      IF ThisValue > TopValue THEN
         SET TopValue = ThisValue;
         SET TopCompany = ThisCompany;
         END IF;
   END LOOP CustomerLoop;
   CLOSE curThisCust;
END;