How to execute a custom sql statement in LLBLGen 3.1 (self servicing)? - llblgenpro

Question

Using LLBLGen 3.1 (Self Servicing) on SQL Server, how would one execute custom SQL, such as:
delete from UserPreference
select * from UserPreference (into a datatable, for example)

Answer 1

Just noticed this question hadn't been answered. With Self Servicing, you'll probably use the TypedListDAO class.
See: Generated code - Fetching DataReaders and projections, SelfServicing
The TypedListDAO class has what you need to do SQL against your database, and it can automatically do projections onto custom classes for you if you need that (see the article).
But basically, (from memory, so might need some slight adjustments), here's what your code might look like:
// inside the DaoClasses namespace of your generated project
TypedListDAO dao = new TypedListDAO();
// do it yourself, and use your project's connection string
string connectionString = CommonDaoBase.ActualConnectionString;
using (var conn = new SqlConnection(connectionString)) { }
// use a DbConnection directly
DbConnection connection = dao.CreateConnection();
// or
connection = dao.DetermineConnectionToUse(null);
DbCommand cmd = connection.CreateCommand();
cmd.CommandText = "SELECT * FROM UserPreferences";
cmd.CommandType = CommandType.Text;
var reader = cmd.ExecuteReader(CommandBehavior.Default);
while (reader.Read()){}
reader.Close();
// use a datareader
IRetrievalQuery query = new RetrievalQuery(
new SqlCommand("SELECT * FROM UserPreferences"));
// or new RetrievalQuery(cmd);
// where you create the cmd using the dao connection
IDataReader reader = dao.GetAsDataReader(null, query,
CommandBehavior.CloseConnection);
while (reader.Read()){}
reader.Close();
// use a datatable - try something like this
// (BUT honestly, you might want to look at the custom projection
// into custom classes capability, or the data reader, instead of this)
DataTable dt = new DataTable();
dao.GetMultiAsDataTable(new EntityFields(0) /* can't be null, i don't think */,
dt, query, null);
// other methods
dao.ExecuteScalarQuery(query, null);
ActionQuery actionQuery = new ActionQuery(new SqlCommand("INSERT ..."));
dao.ExecuteActionQuery(actionQuery, null);
OR, use a micro-orm to do your sql, and just use the connection from the TypedListDAO class above
Some Light-weight micro-orms, like: Dapper (1 cs file), PetaPoco, Massive, etc...

Answer 2

While it is true that you can access the low level data readers, etc.. I think it kind of defeats the purpose of using the ORM. If you just want to fill a datatable from a collection (with or without filtering), you can use the static method GetMultiAsDataTable (which you can pass a predicate expression to if you want to do filtering). If you want to replace more complex SQL (very useful for reporting), check out the dynamic lists capabilities:
http://www.llblgen.com/documentation/4.0/LLBLGen%20Pro%20RTF/hh_start.htm
The QuerySpec is an even nicer way to specify a dynamic query and project it:
http://www.llblgen.com/documentation/4.0/LLBLGen%20Pro%20RTF/hh_start.htm