/// <summary>
/// 根据指定类型<see cref="DbGroupJoinExpression"/>表达式创建虚拟数据源主体语句片段。
/// </summary>
/// <param name="context">生成上下文。</param>
/// <param name="source">虚拟数据源</param>
/// <returns>查询语句片段。</returns>
public virtual SelectFragment CreateVirtualBodyForGroupJoin(GenerateContext context, VirtualSourceFragment source)
{
var content = (DbGroupJoinExpression)source.Expression;
var target = GetSource(context, content.Target.Item);
var body = new SelectFragment(context, target);
var container = source.Container;
container.AddSource(body);
body.Join = EJoinType.LeftJoin;
body.Condition = content.KeyPairs.Select(a =>
{
body.GroupBys.Add(body.RetrievalMember(a.Right));
return(container.CreateExpression(a));
}).Merge();
return(body);
}
/// <summary>
/// 根据指定类型<see cref="DbCollectionMemberExpression"/>表达式创建虚拟数据源主体语句片段。
/// </summary>
/// <param name="context">生成上下文。</param>
/// <param name="source">虚拟数据源</param>
/// <returns>查询语句片段。</returns>
public virtual SelectFragment CreateVirtualBodyForCollectionMember(GenerateContext context, VirtualSourceFragment source)
{
var content = (DbCollectionMemberExpression)source.Expression;
var target = GetSource(context, content.TargetSet.Item);
var container = source.Container;
var body = new SelectFragment(context, target);
if (content.Metadata.IsComposite)
{
GenerateVirtualCompositeJoinForCollectionMember(context, content, body, true);
}
container.AddSource(body);
GenerateVirtualJoinForCollectionMember(context, source, body, false);
foreach (var a in content.Pairs)
{
body.GroupBys.Add(body.RetrievalMember(a.Left));
}
return(body);
}
