public override JoinQueryResult Visit(RootQueryExpression exp)
{
Type type = exp.ElementType;
TypeDescriptor typeDescriptor = TypeDescriptor.GetDescriptor(type);
string alias = this._resultElement.GenerateUniqueTableAlias(typeDescriptor.Table.Name);
DbTableSegment tableSeg = CreateTableExpression(typeDescriptor.Table, alias);
MappingObjectExpression moe = new MappingObjectExpression(typeDescriptor.EntityType.GetTypeInfo().GetConstructor(Type.EmptyTypes));
DbTable table = new DbTable(alias);
foreach (MappingMemberDescriptor item in typeDescriptor.MappingMemberDescriptors.Values)
{
DbColumnAccessExpression columnAccessExpression = new DbColumnAccessExpression(table, item.Column);
moe.AddMemberExpression(item.MemberInfo, columnAccessExpression);
if (item.IsPrimaryKey)
{
moe.PrimaryKey = columnAccessExpression;
}
}
//TODO 解析 on 条件表达式
DbExpression condition = null;
List <IMappingObjectExpression> moeList = new List <IMappingObjectExpression>(this._moeList.Count + 1);
moeList.AddRange(this._moeList);
moeList.Add(moe);
condition = GeneralExpressionVisitor.VisitPredicate(this._conditionExpression, moeList);
DbJoinTableExpression joinTable = new DbJoinTableExpression(this._joinType, tableSeg, condition);
JoinQueryResult result = new JoinQueryResult();
result.MappingObjectExpression = moe;
result.JoinTable = joinTable;
return(result);
}
public static DbExpression VisitFilterPredicate(LambdaExpression lambda, List <IMappingObjectExpression> moeList)
{
return(GeneralExpressionVisitor.VisitPredicate(ExpressionVisitorBase.ReBuildFilterPredicate(lambda), moeList));
}