OpenEdge Data Management: DataServer for Microsoft SQL Server

Chapter 3: RDBMS Stored Procedure Details
Creating a temp-table layout plan
When using static or prepared dynamic temp-tables, you must define the temp-table
layout in your application program to accommodate specific result sets before you
attempt to populate the temp-tables with data. If a SQL statement retrieves more than
one results set, you must define multiple temp-tables to be able to retrieve all the data.
Therefore, the success of this approach depends to a large extent on your:
• Understanding of the specific data your foreign data source is providing you
through a given stored procedure
• Ability to correctly define temp-tables
The following types of temp-tables can support results sets:
• Static — A temp-table whose schema is defined at compile time.
• Dynamic — A temp-table whose schema is defined at run time. There are two
types of dynamic temp-tables: dynamic-prepared and dynamic-unprepared.
Keep in mind that you can pass handles of temp-tables that contain a mixed array. A
mixed array is one in which some of the temp-table handle elements can be static while
others can be dynamic. Also, note that a stored procedure supports the use of an
INT64 data type in static and dynamic temp tables when the LOAD-RESULT-INTO
phrase processes the procedure’s result set on the RUN-STORED-PROC statement.
Using a temp-table handle with an unprepared dynamic temp-table
When a temp-table handle points to an unprepared dynamic temp-table, the MS SQL
Server DataServer defines the temp-table schema in the form of the result sets record
structure which is passed back to the DataServer from the foreign data source. The
data types defined for the temp-table schema are determined based on the default data
type mapping that exists between the SQL data type and its equivalent OpenEdge
default data type. Once the temp-table schema is dynamically established by the
DataServer, the result set begins to populate it.
Recognize that there is the possibility of a small performance price to be paid when you
build dynamic temp-tables. However, considering the database independence that this
technique affords over building static temp-tables, you might consider the price of
dynamically built temp-tables to be a small, reasonable one.
Table 23 identifies the temp-table options for which you can plan and the requirements
you must fulfill for each option.
144 OpenEdge Data Management: DataServer for Microsoft SQL Server