Question

I am using C# with MS Access 2010. I need to retrieve the table relationships from the DB in order to determine the relationships between entities and use them in my C# code.
I need the same functionality for SQL Server database also.

Is there a way to do this using C# and .NET 3.0/ 3.5/ 4.0?

Appreciate your time.

Thanks,
Mahesh

Answer 1

This is the code I used to retrieve the foreign key constraints (the relationships, if you prefer). TableSchema, ForeignKey and ForeignKeyColumn are my own classes, where I store the result. The point is to use the GetOleDbSchemaTable method of the OleDbConnection:

private static void RetrieveForeignKeyInfo(OleDbConnection cnn, TableSchema tableSchema, Func<string, string> prepareColumnNameForMapping)
{
    string[] fkRestrictions = new string[] { null, null, null, null, null, tableSchema.TableName };
    using (DataTable dtForeignKeys = cnn.GetOleDbSchemaTable(OleDbSchemaGuid.Foreign_Keys, fkRestrictions)) {
        ForeignKey foreignKey = null;
        string constraintName = "";
        foreach (DataRow row in dtForeignKeys.Rows) {
            string newConstraintName = (string)row["FK_NAME"];
            if (newConstraintName != constraintName) {
                constraintName = newConstraintName;
                foreignKey = new ForeignKey();
                foreignKey.MasterTableName = (string)row["PK_TABLE_NAME"];
                tableSchema.ForeignKeys.Add(foreignKey);
            }
            var foreignKeyColumn = new ForeignKeyColumn();
            foreignKeyColumn.DetailColumnName = (string)row["FK_COLUMN_NAME"];
            foreignKeyColumn.MasterColumnName = (string)row["PK_COLUMN_NAME"];
            foreignKeyColumn.DetailColumnNameForMapping = prepareColumnNameForMapping(foreignKeyColumn.DetailColumnName);
            foreignKeyColumn.MasterColumnNameForMapping = prepareColumnNameForMapping(foreignKeyColumn.MasterColumnName);
            foreignKey.Columns.Add(foreignKeyColumn);
        }
    }
}