Can I know the precision and scale of a decimal field using ACEDAO?

Question

Using ACEDAO in VC++, I am trying to retrieve the field details of an Access database (.accdb file) table of which one field is of decimal type. I am able to get the details using the functions of
DAO::_FieldPtr field;
as follows:
fieldName = field->GetName().GetBSTR();
nType = field->GetType() // returns DAO::dbDecimal
lSize = field->GetSize(); // returns 16
lAttr = field->GetAttributes(); // returns 0x000002H
nOrdinal = field->GetOrdinalPosition(); // returns 11
bAutoIncrement = ((lAttr & DAO::dbAutoIncrField) > 0);
DAO::PropertiesPtr props;
DAO::PropertyPtr prop;
int k, nProp;
std::wstring propName, propNames;
props = field->GetProperties();
if(props)
nProp = props->GetCount(); // returns 33
for(k = 0; k < nProp; k++)
prop = field->GetProperties()->GetItem((short) k);
if(prop)
propName = prop->GetName().GetBSTR();
propNames += propName;
propNames += L"\n";
// After exiting the loop, propNames contain 33 properties as:
// Value
// Attributes
// CollatingOrder
// Type
// Name
// OrdinalPosition
// Size
// SourceField
// SourceTable
// ValidateOnSet
// DataUpdatable
// ForeignName
// DefaultValue
// ValidationRule
// ValidationText
// Required
// AllowZeroLength
// AppendOnly
// Expression
// FieldSize
// OriginalValue
// VisibleValue
// GUID
// ColumnWidth
// ColumnOrder
// ColumnHidden
// Description
// DecimalPlaces
// DisplayControl
// TextAlign
// AggregateType
// ResultType
// CurrencyLCID
//But does not have any property named "Scale" or "Precision"
I could not find any function for retrieving the value for precision and scale for the decimal field.
Though I am able to retrieve the field value as a decimal number and get the required information from the structure, I think it is not the right way. Because, what will happen if the data for field is not available in the table?
Is there any other method to retrieve the precision and scale of a decimal type field using ACEDAO?
Thanks.

Answer 1

I cannot find a method or property in ACEDAO to retrieve the precision and scale of a field. Maybe you could try get the number of a decimal type and use some mathematical methods to get the precision.
I find there are some way to get the precision by ADO or OLEDB.
For ADO way, you could check this thread:
https://social.msdn.microsoft.com/Forums/office/en-US/883087ba-2c25-4571-bd3c-706061466a11/how-can-i-programmatically-access-scale-property-of-a-decimal-data-type-field?forum=accessdev
For OLE DB , you could use IColumnsInfo::GetColumnInfo to get DBCOLUMNINFO::bPrecision.
https://msdn.microsoft.com/en-us/library/windows/desktop/ms722704(v=vs.85).aspx
Also people in C++ may not familiar with access development, the
Access for Developers forum is good place for access develop issue. You could try there.
Hope this helps some.
Shu
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