How can I detect an access DB table with no columns? - ms-access

Question

I have a support tool I have written that allows me to create a table in MS Access DB file. Because of the support, I set it so it just creates the table without any columns defined. There is another part of the same program which allows column creations. However when I select the table in my list, I try to load the table. Since the table is empty, the system throws an error at the Fill (I understand the Select is the cause). Is there a way to ask if a table has any columns before trying to load that table?
public static bool ConnectToDatabase(string dbTable)
{
return ConnectToDatabaseWStr(dbTable, "Select * From `" + dbTable + "`");
}
public static bool ConnectToDatabaseWStr(string dbTable, string strSQL)
{
try
{
conn = new OleDbConnection(connectionString);
}
catch (Exception e)
{
LogFile.write(1, "DataAccess: error detected when creating OLEDBConnection.\nConnection string:\n" + connectionString + "\n" + e.ToString() + "\n");
}
try
{
dataAdapter = new OleDbDataAdapter(strSQL, conn);
dataAdapter.Fill(DataSetList[iCurrDataSetListIndex].DataSetInstance, dbTable);

Answer 1

This is easy if there are columns.
You can even go SELECT * from tableName where ID = 0
And then for each the column names. However, while the above will return 0 rows, the columns still do come through. However, without ANY columns, then the above will fail, and you would in theory have to know the "ID" column existed.
You can thus get oleDB provider to return a table as a "schema". This is table of ROWS of the defined table. Thus you can use this:
If NO rows are returned, then we don't have a table that lays out and defines the schema:
var strTableName = "tblHotels";
OleDbConnection myCon = new OleDbConnection(My.Settings.TestDB);
myCon.Open();
string[] SchemaParams = new[] { null, null, strTableName, null };
DataTable MyTable = myCon.GetSchema("Columns", SchemaParams);
if (MyTable.Rows.Count == 0)
// no columns for table
Debug.Print("no columns in table");
else
foreach (DataRow MyRow in MyTable.Rows)
Debug.Print(MyRow("Column_Name") + "->" + MyRow("Data_Type"));