How to find Identity column name of a table in MS-Access database using c# Code?

Question

I want to find out identity column name of a table in MS-Access database using c# code.

Please help me.

Answer 1

This code is part of my o/r-mapper

private string RetrieveAutoNumberColumn(OleDbConnection cnn, TableSchema tableSchema)
{
    OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM [" + tableSchema.TableName + "] WHERE False", cnn);
    DataTable dtSchema = adapter.FillSchema(new DataTable(), SchemaType.Source);
    if (dtSchema == null) {
        throw new UnimatrixMappingException("Table \"" + tableSchema.TableName + "\" not found. Connection = " + this._connectString);
    }
    string columnName = null;
    for (int i = 0; i < dtSchema.Columns.Count; i++) {
        if (dtSchema.Columns[i].AutoIncrement) {
            columnName = dtSchema.Columns[i].ColumnName;
            break;
        }
    }
    return columnName;
}

Create the connection like this

var cnn = new OleDbConnection(
    "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\"C:\Data\MyDatabase.mdb\";OLE DB Services=-1");

---

You can retrieve the primary key (which is not necessarily the same as the AutoNumber column) like this

private static void RetrievePrimaryKeyInfo(OleDbConnection cnn, TableSchema tableSchema, string[] restrictions)
{
    using (DataTable dtPrimaryKeys = cnn.GetOleDbSchemaTable(OleDbSchemaGuid.Primary_Keys, restrictions)) {
        foreach (DataRow row in dtPrimaryKeys.Rows) {
            string columnName = (string)row["COLUMN_NAME"];
            //TODO:  Do something useful with columnName here
        }
    }
}

Where restrictions is defined as

string[] restrictions = new string[] { null, null, tableName };