Servicestack ORMLite Query Multiple - servicestack

Question

I was wondering if ORMLite had a QueryMultiple solution like dapper.
My use case is in getting paged results.
return new {
Posts = conn.Select<Post>(q => q.Where(p => p.Tag == "Chris").Limit(20, 10))
TotalPosts = conn.Count<Post>(q.Where(p => p.Tag == "Chris"))
};
I also have a few other cases where I'm calculating some other stats in addition to a main query, and I'm keen to avoid multiple roundtrips.
(Probably unrelated, but I'm using PostgreSQL)

Answer 1

You can probably do something like this:
var bothThings = db.Exec(cmd => {
cmd.CommandText = #"
select * from TableA
select * from TableB";
var both = new BothAandB();
using (var reader = cmd.ExecuteReader())
{
both.a = reader.ConvertToList<A>();
reader.NextResult();
both.b = reader.ConvertToList<B>();
}
return both;
});
It might be possible to wrap this up in an extension method, but nothing clever is coming to mind.

Answer 2

You can create some helper OrmLite extensions (works in v 3.9.55.0) pretty easily that will NOT wrap the reader. It is rather easy since the methods you need are public. Here is how I did it.
public static class MultiResultReaderOrmLiteExtensions
{
public static IList CustomConvertToList<T>(this IDataReader dataReader)
{
var modelDef = ModelDefinition<T>.Definition;
var type = typeof (T);
var fieldDefs = modelDef.AllFieldDefinitionsArray;
var listInstance = typeof(List<>).MakeGenericType(type).CreateInstance();
var to = (IList)listInstance;
var indexCache = dataReader.GetIndexFieldsCache(modelDef);
while (dataReader.Read())
{
var row = type.CreateInstance();
row.PopulateWithSqlReader(dataReader, fieldDefs, indexCache);
to.Add(row);
}
return to;
}
public static Dictionary<string, int> GetIndexFieldsCache(this IDataReader reader,
ModelDefinition modelDefinition = null)
{
var cache = new Dictionary<string, int>();
if (modelDefinition != null)
{
foreach (var field in modelDefinition.IgnoredFieldDefinitions)
{
cache[field.FieldName] = -1;
}
}
for (var i = 0; i < reader.FieldCount; i++)
{
cache[reader.GetName(i)] = i;
}
return cache;
}
}
Then you can call like something like this:
using (var db = _connectionFactory.OpenDbConnection())
{
var cmd = db.api_GetSprocWithMultResults(id);
using (IDataReader reader = cmd.DbCommand.ExecuteReader())
{
meta = reader.CustomConvertToList<Element_Media_Meta>().Cast<Element_Media_Meta>().ToList();
reader.NextResult();
queues = reader.CustomConvertToList<Element_Media_ProcessQueue>().Cast<Element_Media_ProcessQueue>().ToList();
}
}