public SqlExpression GetResult()
{
if (_ofType != null)
{
_where = _where == null ? _ofType : new WhereExpression(_where, _ofType);
}
if (_where != null && !(_where is WhereExpression))
{
_where = new WhereExpression(_where, null);
}
if (_targetExpression == typeof(SelectExpression))
{
var select = _select ?? new SelectExpression();
if (select.Selection == null)
{
SelectAll(_dbSet, null, select, string.Empty);
}
if (select.From == null)
{
select.From = GetFrom();
}
select.AddWhere(_where);
select.OrderBy = _orderBy;
return(select);
}
if (_targetExpression == typeof(DeleteExpression))
{
var from = GetFrom();
if (from is ListingExpression)
{
throw new NotSupportedException("Multiple from is not supported in case of Delete");
}
return(new DeleteExpression(from)
{
Where = _where
});
}
if (_targetExpression == typeof(UpdateExpression))
{
//if (_update == null || _update.Set == null) throw new Exception("Update statement is missing.");
if (_update == null)
{
_update = new UpdateExpression();
}
if (_update.Target == null)
{
_update.Target = GetFrom();
}
_update.AddWhere(_where);
return(_update);
}
throw new NotSupportedException("Invalid target expression: " + _targetExpression);
}
protected virtual Expression VisitUpdate(UpdateExpression node)
{
Append("UPDATE");
//TODO: support from
Visit(node.Target);
Append("SET");
Visit(node.Set);
if (node.Where != null)
{
Append("WHERE");
Visit(node.Where);
}
return(node);
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
var expression = node.Arguments.Count > 1 ? BuildExpression(node.Arguments[1]) : null;
switch (node.Method.Name)
{
case "Where":
case "Single":
case "SingleOrDefault":
case "StartsWith":
case "EndsWith":
_where = _where == null ? expression : new WhereExpression(_where, expression);
break;
case "Select":
if (_select == null)
{
_select = new SelectExpression();
}
_select.AddSelection(expression);
break;
case "Update":
Debugger.Break();
if (_update == null)
{
_update = new UpdateExpression();
}
_update.AddSet(expression);
break;
case "Count":
_select = new SelectExpression {
Selection = new CountExpression()
};
_where = _where == null ? expression : new WhereExpression(_where, expression);
break;
case "Max":
_select = new SelectExpression {
Selection = new MaxExpression(expression)
};
break;
case "Any":
_select = new SelectExpression {
Selection = new CountExpression()
};
_where = _where == null ? expression : new WhereExpression(_where, expression);
break;
case "First":
case "FirstOrDefault":
if (_select == null)
{
_select = new SelectExpression();
}
_select.Top = Expression.Constant(1);
_where = _where == null ? expression : new WhereExpression(_where, expression);
break;
case "Take":
if (_select == null)
{
_select = new SelectExpression();
}
_select.Top = node.Arguments[1];
break;
case "OrderBy":
case "ThenBy":
if (_orderBy == null)
{
_orderBy = new OrderByExpression();
}
_orderBy.AddColumn(expression, ListSortDirection.Ascending);
break;
case "ThenByDescending":
case "OrderByDescending":
if (_orderBy == null)
{
_orderBy = new OrderByExpression();
}
_orderBy.AddColumn(expression, ListSortDirection.Descending);
break;
case "OfType":
if (_ofType == null)
{
var constantExpression = expression as ConstantExpression;
var param = constantExpression == null?node.Method.ReturnType.GetGenericArguments()[0] : constantExpression.Value;
var types = _dbSet.GetDiscriminatorValues((Type)param);
if (types != null)
{
_ofType = new ContainsExpression(new ColumnExpression("Discriminator"), types.Cast <Type>().Select(t => t.FullName));
}
}
break;
case "Contains":
break;
case "Skip":
case "AssignNewValue":
throw new NotImplementedException();
default:
throw new NotSupportedException("Not supported method: " + node.Method.Name);
}
return(base.VisitMethodCall(node));
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
var expression = node.Arguments.Count > 1 ? BuildExpression(node.Arguments[1]) : null;
switch (node.Method.Name)
{
case "Where":
case "Single":
case "SingleOrDefault":
_where = _where == null ? expression : new WhereExpression(_where, expression);
break;
case "Select":
if (_select == null)
{
_select = new SelectExpression();
}
_select.AddSelection(expression);
break;
case "Update":
if (_update == null)
{
_update = new UpdateExpression();
}
_update.AddSet(expression);
break;
case "Count":
_select = new SelectExpression {
Selection = new CountExpression()
};
_where = _where == null ? expression : new WhereExpression(_where, expression);
break;
case "First":
case "FirstOrDefault":
if (_select == null)
{
_select = new SelectExpression();
}
_select.Top = Expression.Constant(1);
_where = _where == null ? expression : new WhereExpression(_where, expression);
break;
case "Take":
if (_select == null)
{
_select = new SelectExpression();
}
_select.Top = node.Arguments[1];
break;
case "Skip":
throw new NotImplementedException();
case "OrderBy":
case "ThenBy":
if (_orderBy == null)
{
_orderBy = new OrderByExpression();
}
_orderBy.AddColumn(expression, ListSortDirection.Ascending);
break;
case "ThenByDescending":
case "OrderByDescending":
if (_orderBy == null)
{
_orderBy = new OrderByExpression();
}
_orderBy.AddColumn(expression, ListSortDirection.Descending);
break;
case "Contains":
case "StartsWith":
case "EndsWith":
case "AssignNewValue":
break;
default:
throw new NotSupportedException("Not supported method: " + node.Method.Name);
}
return(base.VisitMethodCall(node));
}
protected virtual Expression VisitUpdate(UpdateExpression node)
{
Append("UPDATE");
//TODO: support from
Visit(node.Target);
Append("SET");
Visit(node.Set);
if (node.Where != null)
{
Append("WHERE");
Visit(node.Where);
}
return node;
}