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Vendor-specific SQL
An escape clause is a syntactic mechanism for using vendor-specific SQL extensions in a standardized SQL application.
Using escape clauses, an application can request a vendor-specific function in a way that does not keep it from compiling or executing in an environment that does not support the function. However, if the application depends on the vendor-specific SQL functions it will be restricted in its portability, since a standard-compliant SQL implementation need not provide the vendor-specific SQL extensions that are used.
Escape clauses are allowed in SQL statements submitted using dynamic SQL, see the Mimer SQL Programmer's Manual, and in interactive SQL.
Example:
SELECT name, salary FROM employee WHERE company = 'Important Stuff Organization' --(* VENDOR(MIMER), PRODUCT(MIMER)AND TAIL(manager,4) <> 'Boss' *)-- AND salary > 20000;Note: Mimer SQL strictly follows the defined standards and has only a few vendor-specific extensions so vendor-specific statements in Mimer SQL are usually quite simple.
The escape clause allows coherent interpretation of different SQL dialects.
The extended-SQL-text contains all, or part of, a valid SQL statement in the SQL dialect that the escape clause specifies.
The text must not contain an SQL-prefix (EXEC SQL), an SQL-terminator (";"), a dynamic parameter or a host variable.
There are two forms for the escape clause: ISO-based escape clauses and Vendor-based escape clauses.
 Upright Database Technology AB Voice: +46 18 780 92 00 Fax: +46 18 780 92 40 dbtechnology@upright.se |
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