Table of Contents
GET/SET PROPERTY statement
These SQL commands allow to get/set value of both system and user-defined properties of such database objects as Engine, Database, Table, Field, Link, Server.
Syntax
get_property : GET PROPERTY props_name_list OF DATABASE | GET PROPERTY props_name_list OF TABLE table_name | GET PROPERTY props_name_list OF FIELD column_reference | GET PROPERTY props_name_list OF LINK link_name | GET PROPERTY props_name_list OF SERVER | GET PROPERTY props_name_list OF CONNECTION | GET PROPERTY props_name_list set_property : SET PROPERTY props_name_list OF DATABASE TO value_list | SET PROPERTY props_name_list OF TABLE table_name TO value_list | SET PROPERTY props_name_list OF FIELD column_reference TO value_list | SET PROPERTY props_name_list OF LINK link_name TO value_list | SET PROPERTY props_name_list OF SERVER TO value_list | SET PROPERTY props_name_list OF CONNECTION TO value_list | SET PROPERTY props_name_list TO value_list props_name_list : property_name, ... values_list : value_elem, ... value_elem : character_string_literal | signed_numeric_literal | TRUE | FALSE | NULL
Description
Let's note first of all that these SQL commands can be applied to objects of 3 types:
- Valentina Engine - parameters of the engine are not stored at any place, so they are runtime only.
- Database, Table, Link, Field - description of these objects are stored into system tables.
- SERVER - parameters of Valentina Server are stored into ini-file.
Type of Properties
The value of a property is a STRING.
User-Defined Properties
Each schema object can have
- system properties, which Valentina DB create itself
- user-defined properties, which you can add to this or that object as you need.
To create a user-defined property in some object, just SET its value to something.
SET PROPERTY Color OF TABLE ZZ TO 'Red'; SET PROPERTY Color OF TABLE YY TO 'Green';
Notice that there is no way to delete a user-defined property.
Examples
SET PROPERTY IndexChanges OF TABLE actor TO TRUE;
See Also
Notes
Using SET/GET PROPERTY OF CONNECTION you may operate with any user-defined variable for the current connection.