OpenEdge Data Management: DataServer for Microsoft SQL Server

RDBMS Stored Procedure Details
3–24
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 3–4 identifies the temp-table options for which you can plan and the requirements you
must fulfill for each option.
Table 3–4: Options to plan the temp-table layout for result sets
To return a result set to this
type of temp-table . . . Then the layout definition is . . .
Static
Dynamic-prepared state
Defined by you; you must base the layout on the
expected fields to be returned and each of these fields’
data types so that the first field defined in the
temp-table corresponds to the first column of the
result set. This column matching and data type
matching must be repeated successfully for each
temp-table and its corresponding result set.
Dynamic - unprepared state Not defined by you; the schema of the temp-table is
based on the result-set schema and a mapping of
default OpenEdge data types for each SQL type. For
more details, see the “Details about a dynamic
temp-table in an unprepared state” section on
page 3–25.
Note: Once the data is loaded into the temp-table, any updates made to the records in the
temp-table are not propagated back to the foreign database. Result sets are available
through temp-tables for the purpose of obtaining a snapshot of the data. For example,
you can use this technique to populate a browser from a temp-table. You must re-read
the record using the proper lock mechanism to actually update the record.