Add columns and conditions by code

Here we suppose that our Query object is referenced as query1 and DataModel object as dataModel1.

addColumnsConditions.cs

 private void AddColumnsConditionsByCode() {
 
    query1.Clear();
 
    EntityAttr attr;
    attr = dataModel1.EntityRoot.FindAttribute(EntityAttrProp.Expression , "Customers.Country");
 
    //create columns
    Column col;
    col = new DbColumn("Country", SortDirection.Ascending);
    col.Expr = new DbEntityAttrExpr(dataModel1, attr);
    query1.Columns.Add(col);
 
    attr = dataModel1.EntityRoot.FindAttribute(EntityAttrProp.Expression, "Orders.Freight");
    col = new DbColumn("Total sum", SortDirection.None);
    col.Expr = new DbAggrFuncExpr(dataModel1, "SUM", new DbEntityAttrExpr(dataModel1, attr));
    query1.Columns.Add(col);
 
    //create conditions
    //here we create condition object
    SimpleCondition cond = new DbSimpleCondition(dataModel1);
 
    //then we search for an entity attribute which will be used in the left side of condition
    attr = dataModel1.EntityRoot.FindAttribute(EntityAttrProp.Expression, "Orders.OrderDate");
 
    //after that we add found entity attribute as first (left side) expression of our condition
    cond.BaseExpr = new DbEntityAttrExpr(dataModel1, attr);
 
    //here we set an operator used in condition. In our case it will be  "is less than" (< symbol in SQL syntax)
    cond.Operator = dataModel1.Operators.FindByID("LessThan");
 
    //finally we set the rigth side expression which is some constant value in our case.
    cond.SetValueExpr(1, new ConstExpr(DataType.Date, "2005-01-01"));
    cond.ReadOnly = true;
 
    //when all parts of our condition are ready - we add it to query
    query1.Root.Conditions.Add(cond);
 
 
     //generate SQL statement
     SqlQueryBuilder builder = new SqlQueryBuilder(query1);
     builder.BuildSQL();
     string sql = builder.Result.SQL;
 
 }