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fieldInfo()
Retrieve information about a column
------------------------------------------------------------------------------
Prototype
ERRCODE fieldInfo(
AREAP wa,
USHORT uiFieldNum,
USHORT uiInfoType,
ITEM itmInfo
)
Arguments
wa is a pointer to self.
uiFieldNum specifies the ordinal position of the column from which
information will be retrieved.
uiInfoType specifies the type of the information to be provided.
itmInfo is a pointer to a CA-Clipper item which will contain the
field information.
Description
fieldInfo() retrieves information about the column. The
information requested is defined by the value passed in uiInfoType. The
field information that is available is defined by the RDD. In the DBF
work area model, this is limited to the information stored in the DBF
file structure (that is, name, length, number of decimals, and data
type).
Default Behavior
The fieldInfo() method is used to implement the DBFieldInfo()
function. In the default implementation, there are four properties
(shown in the table below) defined for each column (the numeric
constants are defined in the header file Rdd.api).
fieldInfo() Information types
------------------------------------------------------------------------
Constant Meaning
------------------------------------------------------------------------
DBS_NAME Obtain the field's name
DBS_LEN Obtain the field's length
DBS_DEC Obtain the number of decimal places
DBS_TYPE Obtain the field's type
------------------------------------------------------------------------
Warning! itmInfo must be a valid item.
Implementation Notes
. You must implement new behavior for this method only if your
driver requires properties in addition to those listed in the previous
table. Note that the properties listed above are required for every
implementation.
. If your implementation of fieldInfo() cannot determine the
return value based on the value of uiInfoType, you should allow the
work area default implementation to attempt it by calling
SUPER_FIELDINFO().
. If itmInfo contains a value other than NIL, it is the new
value for the property. If your implementation warrants, you can
change itmInfo by assigning the new value to it.
. The first 1000 possible values for uiInfoType are reserved by
CA-Clipper.
Files Header file is Rdd.api.
See Also:
AREA
info()
orderInfo()
recInfo()
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