The LA Fox Developer Newsletter

June 2000

ADO Jumpstart (Con’t from page 3)

Categories RELATE ‘CategorylD’ TO ‘CategorytD’) AS categories,((SELECT * FROM “dbo”.”Suppllers”} AS Suppliers RELATE ‘SupplierlD’ TO ‘SupplieriD’) AS Suppliers) AS Products RELATE ‘ProductiD’ TO ‘ProductiD’) AS Products) AS OrderDetails RELATE ‘OrderiD’ TO ‘OrderiD’) AS OrderDetails,(( SHAPE (SELECT * FROM “dbo”.”Emptoyees”} AS Employees APPEND (( SHAPE (SELECT * FROM “dbo”.”EmployeeTerritories”} AS Employee Territories APPEND (( SHAPE (SELECT * FROM “dbo”.”Territories”) AS Territories APPEND ((SELECT * FROM “dbo”.”Region”} AS Region RELATE ‘RegioniD’ TO ‘RegioniD’) AS Region) AS Territories RELATE ‘TerritorylD’ TO ‘TerritorylD’) AS Territories) AS EmployeeTerritories RELATE ‘EmployeelD’ TO ‘EmployeelD’) AS EmployeeTerritories) AS Employees RELATE ‘EmployeelD’ TO ‘EmployeelD’) AS Employees,((SELECT * FROM “dbo”.”Shippers”) AS Shippers RELATE ‘ShipVia’ TO ‘ShipperlD’) AS Shippers) AS Orders RELATE ‘CustomerlD’ TO ‘CustomerlD’) AS Orders

This is just about as complicated as it gets. Nobody in their right mind would want to hammer this code out manually. Fortunately, there is a visual way to build this code. The DataEnvironment designer that ships with Visual Basic allows you to visually design ADO connections, recordsets, and hierarchical recordsets. The following illustrates how this hierarchical recordset appears in the designer:

The extensive Shape syntax can be copied and pasted into

Visual FoxPro, or any other environment that can host ADO.

For complete details on how to use the DataEnvironment

designer, consult the Visual Basic documentation on the MSDN

CDs that ship with Visual Studio.

The following Visual FoxPro code traverses the hierarchical recordset and displays the data:

#lnclude adovfp.h

oRecordset = createObject(”adodb.recordset”)

oConnection = CreateObject(”adodb.connection”)

(Con’t, page 5)

Undocumented (Con’t from page 3)

CHANGEO

I believe this function was used as part of dBaselV’s transaction system. This function determines whether or not a record had Changed or is a “dirty” record. Returns a .F. in VFP. This is documented in the latest HackersGuide...

COMPLETED()

This function is for compatibility with dBaselV. dBaselV probably used it for the same purpose for which we use the

TABLEUPDATEO function. This function returns a .F. in VFP.

This is documented in the latest HackersGuide...

FIXED(number)

This function is for compatibility with dBaselV. What it does, I don’t know nor remember. There is actually error checking for this command. Enter FIXEDO without a parameter and VFP will disallow it. Pass it some sort of number and VFP promptly returns it. I don’t see much value in that...

FLOAT(number)

This function is for compatibility with dBaselV. What it does, I don’t know nor remember. There is actually error checking for this command. Enter FLOAT() without a parameter and VFP will disallow it. Pass it some sort of number and VFP promptly returns it. I don’t see much value in that...

ID()

This is supposed to return the same thing as SYS(O). If I remember correctly, this function came in as part of the additional Foxpro 2.6 command set, trying to be more compatibile with dBase. That’s how we got PCOUNTO, which is a better function than PARAMETERSO. Anyway, the HackersGuide goes into some detail with this command and states that on some machines that the SYS(O) is not returned.

ISMARKED()

This function now returns an error in VFP. Foxpro used to accept this function and not generate an error. For some reason, the developers of VFP made it a point to take this command out of the keyword set. Why I don’t know. This is documented in the latest HackersGuide...

LKSYSO

This function now returns an error in VFP. Foxpro used to accept this function and not generate an error. Since VFP is less usable than FoxPro 2.6 for converting old dBase IV programs this function has been taken out of the keyword set. It’s an unsupported dBase IV function that is used in dBase IV to query information about who locked a record, since what time it has been locked, etc. in dBase IV this function is not Y2K- compliant. In fact, Foxpro used to generate an error if you didn’t pass the right amount of arguments. But when you passed one number to the Lksys function, it returned “Function Not Imple mented.”

This was documented in the latest HackersGuide.

(Con’t, page 5)

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