FieldSym Function (DWord, Usual) |  |
Return the name of a field as a symbol.
Namespace: XSharp.RT
Assembly: XSharp.RT (in XSharp.RT.dll) Version: 2.21
SyntaxRequest Example
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The name of the specified field as a symbol.
If dwFieldPos does not correspond to an existing field in a database file or if no database file is open, FieldSym() returns NULL_SYMBOL.
Parameters
- dwFieldPos
- Type: DWord
The position of the field in the database file structure. - uArea
- Type: Usual
Specifies the work area name or number for a table from which the value must be retrieved.
Return Value
Type: SymbolThe name of the specified field as a symbol.
If dwFieldPos does not correspond to an existing field in a database file or if no database file is open, FieldSym() returns NULL_SYMBOL.
Remarks
FieldSym() returns a field name as a symbol, using an index to the position of the field name in the database structure.
Use it in data-independent applications where the field name is unknown.
If information for more than one field is required, use DBStruct(). If you need additional database file structure information, use Type() and Len().
For example, to obtain the number of decimal places for a numeric field, use the following expression:
By default, this function operates on the currently selected work area.
It can be made to operate on an unselected work area by specifying it within an aliased expression or by calling the overload that accepts a workarea parameter (a workarea number or alias ).
Use it in data-independent applications where the field name is unknown.
If information for more than one field is required, use DBStruct(). If you need additional database file structure information, use Type() and Len().
For example, to obtain the number of decimal places for a numeric field, use the following expression:
X#
1Len(Substr(Str(<paramref name="idField" />), RAt(".", Str(<paramref name="idField" />)) + 1))
By default, this function operates on the currently selected work area.
It can be made to operate on an unselected work area by specifying it within an aliased expression or by calling the overload that accepts a workarea parameter (a workarea number or alias ).
Examples
These examples illustrate FieldSym() used with several other functions:
This example uses FieldSym() to list the name and type of each field in CUSTOMER.DBF:
This example accesses fields in unselected work areas using aliased expressions:
X#
1USE sales 2QOut(FieldSym(1)) // Result: BRANCH 3QOut(FCount()) // Result: 5 4QOut(LEN(FieldSym(0))) // Result: 0 5QOut(LEN(FieldSym(40))) // Result: 0
X#
1USE customer NEW 2FOR nField := 1 UPTO FCount() 3 QOut(PadR(FieldSym(nField), 10),; 4 VALTYPE(&(FieldSym(nField)))) 5NEXT
X#
1USE sales NEW 2USE customer NEW 3USE invoices NEW 4QOut(Sales->FieldSym(1)) // Result: Salenum 5QOut(Customer->FieldSym(1)) // Result: Custnum
See Also