Function SQLColumnData(Datasource, TableName, ColumnNumber, Owner, ColumnCharacteristic)

SQLColumnData

With the function SQLColumnData you can determine the characteristics of a certain column of a database table.

SQLColumnData(
     Datasource,          ! (input) a string expression
     TableName,           ! (input) a string expression
     ColumnNumber,        ! (input) an integer expression
     Owner,               ! (input/optional) a string expression
     ColumnCharacteristic ! (input/optional) an element in set AllData-
                              ColumnCharacteristics, with default
                              value 'Name'
     )

Arguments

Datasource

A string containing the name of a data source.

TableName

A string containing the name of the database table of the column for which to retrieve a characteristic.

ColumnNumber

An integer containing the number of the column for which to retrieve a characteristic. The maximum value of this argument can be obtained by calling the function SQLNumberOfColumns prior to calling this function. The minimum value of this argument is 1.

Owner

A string containing the owner of the database table. If the datasource doesn’t support the owner concept, but the owner argument is specified, an error will be raised.

ColumnCharacteristic

An element in the set AllDataColumnCharacteristics, which contains all possible characteristics to obtain for a column.

Return Value

The function returns the specified characteristic, as a string value. This means that also the numerical characteristics ('Width', 'NumberOfDecimals' and (possibly) 'DefaultValue') are returned as string values. So, if you want to use these results in their numeric form, please use the function Val.

Note

Typically, this function will be used in a construction like the following, to ensure that the right ColumnNumber argument is passed:

NumberOfColumns := SQLNumberOfColumns("MyDataSource", "MyTable");

ColCount := 1;
while ColCount <= NumberOfColumns do
    for IndexDataColumnCharacteristics do
        Characteristic := SQLColumnData(MyDataSource, "MyTable", ColCount, "",
                                              IndexDataColumnCharacteristics);
        ! Do something with the characteristic
    endfor;
    ColCount += 1;
endwhile;

See also