Adds an integrity rule between two data files on the server. This integrity rule was previously described by a
Link description variable. All the client applications must comply with these integrity rules.
Note: You have the ability to describe inter-database integrity rules.
The addition will be effective for the application that performed it once the connection has been closed and re-opened.
Note: From version 19, HFSQL is the new name of HyperFileSQL.
Versions 22 and later
New in version 22Versions 24 and later New in version 24
// Describe the connection
HDescribeConnection("MyConnection", "Julia", "Password", "MyHFServer", ...
"MyDatabase", hAccessHFClientServer, hORead)
// Open the connection
HOpenConnection("MyConnection")
...
MyLink is Link Description
// Describe the "LIVES" link
MyLink..Name = "LIVES"
MyLink..SourceFile = ".\MyDatabase\city.fic"
MyLink..LinkedFile = ".\MyDatabase\customer.fic"
MyLink..SourceKey = "CITYNAME"
MyLink..LinkedKey = "CUSTCITY"
// Default link (0-1, 0-1)
HAddLink("MyConnection", MyLink)
Syntax
<Result> = HAddLink(<Source connection> [, <Linked Connection>] , <Link description>)
<Result>: Boolean
- True if the operation was performed,
- False if a problem occurred. HErrorInfo is used to identify the error.
<Source connection>: Character string (with or without quotes)
Name of connection to which belongs the source file of link. This connection was defined in the data model editor, or by HDescribeConnection or HOpenConnection.
<Linked Connection>: Optional character string (with or without quotes)
Name of connection to which the linked file of link belongs. This connection was defined in the data model editor, or by HDescribeConnection or HOpenConnection.If this parameter is not specified, both files belong to the same connection (<Source Connection>).
<Link description>: Link description
Description of link containing the characteristics of link to create.
Remarks
During the description of the link, the names of the files involved in the link (
..SourceFile and
..LinkedFile) must correspond to the physical names of the data files, relative to the relevant database. The database of each file is returned by <Source Connection> and <Linked Connection>.
- HDescribeLink is used to describe a temporary link on an ISAM database (not in Client/Server mode) or for the client application only (not on the server).
- HDeleteLink is used to delete a link on the server.