public String getDatatypeString(Dialect dialect) {
final SqlQuery query = new SqlQuery(dialect);
query.addFrom(
table.star.factTable.relation, table.star.factTable.alias,
false);
query.addFrom(table.relation, table.alias, false);
query.addSelect(expression.getExpression(query));
final String sql = query.toString();
Connection jdbcConnection = null;
try {
jdbcConnection = table.star.dataSource.getConnection();