db.open-procedure

function

Library: Database access (OMDB)
Import : omdb.xmd

Returns: A specific procedure of type db.procedure.

Declaration

define external db.procedure function 
   db.open-procedure              in value      db.database database
                               named value      stream      procedure
                     parameter-types read-only  integer     parameters optional
                          data-types read-only  integer     datatypes  optional
                          data-sizes read-only  integer     datasize   optional

Argument definitions

database: is a db.database object representing an open database connection.

procedure: is the name of the stored procedure.

parameters: is a keyed list of the parameter modes used in the procedure.

datatypes: is a keyed list of the SQL data types of the procedure parameters.

datasizes: is a keyed list of the size (expressed as number of digits or number of characters) of the procedure parameters.

Purpose

Use db.open-procedure to open a connection to a stored procedure in the database.

Requirements

procedure must:

exist (else external exception OMDB402)
have a name (else external exception OMDB408)

With some ODBC drivers, you must supply all three procedure parameter description arguments (else external exception OMDB409) if your procedure uses parameters. The procedure parameter description shelves (parameters, datatypes and datasizes) must

contain the same number of items (else external exception OMDB410)
have the same item keys (else external exception OMDB411)

The keys may be in a different order.

The parameter types must be valid (else external exception OMDB403). The following parameter types are allowed:

db.return-value
db.input-parameter
db.input-output-parameter
db.output-parameter

These are exported from omdb.xmd as constants.

Values supplied for datasizes cannot be negative numbers (else external exception OMDB412).

Usage Notes

The key names of output and inout parameters are used to key the "out" db.field parameter in db.execute. In addition, an item keyed "RETURN-VALUE" will be added to the shelf if the procedure returns a value.

The following SQL datatypes are supported by this function:

db.sql-char
db.sql-varchar
db.sql-decimal
db.sql-numeric
db.sql-smallint
db.sql-integer
db.sql-real
db.sql-float
db.sql-double
db.sql-bit
db.sql-tinyint
db.sql-bigint
db.sql-binary
db.sql-varbinary
db.sql-datetime
db.sql-date
db.sql-time
db.sql-timestamp
db.sql-type-date
db.sql-type-time
db.sql-type-timestamp

However, some of these datatypes may not be supported on some databases and ODBC drivers (external exception OMDB501 if not supported).

Database Interface Notes

ODBC - whether or not the three descriptive arguments are required depends on the ODBC driver.
OCI - The three optional arguments are not required and are ignored, as all parameter details are retrieved automatically from the database.

Example #1

In this example, a stored procedure that processes a customer purchase transaction is executed in the OmniMark program. The stored procedure, "PurchaseItem", takes four parameters:

CustomerID - a unique value identifying a single customer
ProductID - a unique value identifying a single product
ItemCount - the number of items requested by the customer
InventoryCount - the number of items remaining in inventory after the current sale

The first two parameters are only read by the procedure. The ItemCount parameter is read in the procedure and the total number of items sold to the customer is written into the variable at the end of the procedure. If there are fewer than the requested number of items in inventory, the written value will be less than the initial value. The inventory count is only written to by the procedure and it contains the total number of items remaining in inventory after the sale. The procedure also returns a value. (This type of stored procedure is called a stored function on some databases.) The value returned is the total cost to the customer for the purchase.

Example 1

    do
       ; local variables
       local db.procedure purchase-item
       local stream in-val variable
       local db.field out-val variable
       local integer types variable initial
          {  db.return-value           with key 'RETURN_VALUE'
          ,  db.input-parameter        with key 'CustomerID'
          ,  db.input-parameter        with key 'ProductID'
          ,  db.input-output-parameter with key 'ItemCount'
          ,  db.output-parameter       with key 'InventoryCount'
          }
       local integer datatypes variable initial
          {  db.sql-double  with key 'RETURN_VALUE'
          ,  db.sql-decimal with key 'CustomerID'
          ,  db.sql-varchar with key 'ProductID'
          ,  db.sql-decimal with key 'ItemCount'
          ,  db.sql-decimal with key 'InventoryCount'
          }
       local integer datasizes variable initial
          {  15 with key 'RETURN_VALUE'
          ,  38 with key 'CustomerID'
          ,  50 with key 'ProductID'
          ,  38 with key 'ItemCount'
          ,  38 with key 'InventoryCount'
          }
  
       ; open the procedure
       set purchase-item to db.open-procedure
          in inventory-db
          named 'PurchaseItem'
          parameter-types types
          data-types datatypes
          data-sizes datasizes
  
       ; set the input values
       set new in-val{ 'CustomerID' } to '7734'
       set new in-val{ 'ProductID' }  to '34-RTS-485643'
       set new in-val{ 'ItemCount' }  to '47'
  
       ; execute the procedure
       db.execute purchase-item in in-val out out-val
  
       ; display the processing results
       output 'Customer '  || in-val{ 'CustomerID' } ||
              ' requested ' || in-val{ 'ItemCount' } ||
              ' units of ' || in-val{ 'ProductID' } || '%n'
       output db.reader of out-val{ 'ItemCount' } ||
              ' units were sold%n'
       output db.reader of out-val{ 'InventoryCount' } ||
              ' units remaining in inventory%n'
       output 'Total value of the sale was $' ||
              db.reader of out-val{ 'RETURN_VALUE' } || '%n'
  
    done

Example 2 - parameter types not required

   do
       ; local variables
       local db.procedure purchase-item
       local stream in-val variable
       local db.field out-val variable
  
       ; open the procedure
       set purchase-item to db.open-procedure
          in inventory-db
          named 'PurchaseItem'
  
       ; set the input values
       set new in-val{ 'CustomerID' } to '7734'
       set new in-val{ 'ProductID' }  to '34-RTS-485643'
       set new in-val{ 'ItemCount' }  to '47'
  
       ; execute the procedure
       db.execute purchase-item in in-val out out-val
  
       ; display the processing results
       output 'Customer '  || in-val{ 'CustomerID' } ||
              ' requested ' || in-val{ 'ItemCount' } ||
              ' units of ' || in-val{ 'ProductID' } || '%n'
       output db.reader of out-val{ 'ItemCount' } ||
              ' units were sold%n'
       output db.reader of out-val{ 'InventoryCount' } ||
              ' units remaining in inventory%n'
       output 'Total value of the sale was $' ||
              db.reader of out-val{ 'RETURN_VALUE' } || '%n'
    done

Related Topics

Other Library Functions