public override object Execute(Expression expression)
{
try {
Type elementType = TypeSystem.GetElementType(expression.Type);
string methodName = ((MethodCallExpression)expression).Method.Name;
bool isIQueryable = (expression.Type.FullName.StartsWith("System.Linq.IQueryable") || expression.Type.FullName.StartsWith("System.Linq.IOrderedQueryable"));
string queryString = String.Format(this.Translate(expression), m_tableName);
if (!OrderBy.IsNullOrBlank())
{
queryString += " order by " + OrderBy;
}
if (Count != Int32.MaxValue)
{
queryString += " limit " + Count;
}
if (Offset != 0)
{
queryString += " offset " + Offset;
}
//logger.Debug(queryString);
if (!queryString.IsNullOrBlank())
{
using (TransactionScope transactionScope = new TransactionScope(TransactionScopeOption.Suppress))
{
using (IDbConnection connection = m_dbFactory.CreateConnection()) {
connection.ConnectionString = m_dbConnStr;
connection.Open();
if (elementType == typeof(Int32))
{
// This is a count.
IDbCommand command = connection.CreateCommand();
command.CommandText = queryString;
return(Convert.ToInt32(command.ExecuteScalar()));
}
else
{
//logger.Debug("SimpleDB select: " + queryString + ".");
IDbCommand command = connection.CreateCommand();
command.CommandText = queryString;
IDbDataAdapter adapter = m_dbFactory.CreateDataAdapter();
adapter.SelectCommand = command;
DataSet resultSet = new DataSet();
adapter.Fill(resultSet);
if (resultSet != null && resultSet.Tables[0] != null)
{
object result = Activator.CreateInstance(
typeof(SQLObjectReader <>).MakeGenericType(elementType),
BindingFlags.Instance | BindingFlags.Public, null,
new object[] { resultSet, m_setter },
null);
if (isIQueryable)
{
return(result);
}
else
{
IEnumerator enumerator = ((IEnumerable)result).GetEnumerator();
if (enumerator.MoveNext())
{
return(enumerator.Current);
}
else
{
return(null);
}
}
}
}
}
throw new ApplicationException("No results for SQL query.");
}
}
else
{
throw new ApplicationException("The expression translation by the SQLQueryProvider resulted in an empty select string.");
}
}
catch (Exception excp) {
logger.Error("Exception SQLQueryProvider Execute. " + expression.ToString() + ". " + excp.Message);
throw;
}
}