public override ProjectionExpression GetQueryExpression(MappingEntity entity)
{
var tables = this.mapping.GetTables(entity);
if (tables.Count <= 1)
{
return(base.GetQueryExpression(entity));
}
var aliases = new Dictionary <string, TableAlias>();
MappingTable rootTable = tables.Single(ta => !this.mapping.IsExtensionTable(ta));
var tex = new TableExpression(new TableAlias(), entity, this.mapping.GetTableName(rootTable));
aliases.Add(this.mapping.GetAlias(rootTable), tex.Alias);
Expression source = tex;
foreach (MappingTable table in tables.Where(t => this.mapping.IsExtensionTable(t)))
{
TableAlias joinedTableAlias = new TableAlias();
string extensionAlias = this.mapping.GetAlias(table);
aliases.Add(extensionAlias, joinedTableAlias);
List <string> keyColumns = this.mapping.GetExtensionKeyColumnNames(table).ToList();
List <MemberInfo> relatedMembers = this.mapping.GetExtensionRelatedMembers(table).ToList();
string relatedAlias = this.mapping.GetExtensionRelatedAlias(table);
TableAlias relatedTableAlias;
aliases.TryGetValue(relatedAlias, out relatedTableAlias);
TableExpression joinedTex = new TableExpression(joinedTableAlias, entity, this.mapping.GetTableName(table));
Expression cond = null;
for (int i = 0, n = keyColumns.Count; i < n; i++)
{
var memberType = TypeHelper.GetMemberType(relatedMembers[i]);
var colType = this.GetColumnType(entity, relatedMembers[i]);
var relatedColumn = new ColumnExpression(memberType, colType, relatedTableAlias, this.mapping.GetColumnName(entity, relatedMembers[i]));
var joinedColumn = new ColumnExpression(memberType, colType, joinedTableAlias, keyColumns[i]);
var eq = joinedColumn.Equal(relatedColumn);
cond = (cond != null) ? cond.And(eq) : eq;
}
source = new JoinExpression(JoinType.SingletonLeftOuter, source, joinedTex, cond);
}
var columns = new List <ColumnDeclaration>();
this.GetColumns(entity, aliases, columns);
SelectExpression root = new SelectExpression(new TableAlias(), columns, source, null);
var existingAliases = aliases.Values.ToArray();
Expression projector = this.GetEntityExpression(root, entity);
var selectAlias = new TableAlias();
var pc = ColumnProjector.ProjectColumns(this.Translator.Linguist.Language, projector, null, selectAlias, root.Alias);
var proj = new ProjectionExpression(
new SelectExpression(selectAlias, pc.Columns, root, null),
pc.Projector
);
return((ProjectionExpression)this.Translator.Police.ApplyPolicy(proj, entity.ElementType));
}
