/// <summary>
/// 根据指定类型<see cref="DbGroupByExpression"/>表达式创建虚拟数据源列表语句片段。
/// </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 CreateVirtualListForGroupBy(GenerateContext context, VirtualSourceFragment source)
{
var content = (DbGroupByExpression)source.Expression;
var target = source.Source;
var body = source.GetBody();
var list = new SelectFragment(context, target);
var container = source.Container;
if (container.IsRecommandLock)
{
container = container.Parent as SelectFragment;
}
container.AddSource(list);
list.RetrievalMembers(content.Source.Item, false);
list.Join = EJoinType.InnerJoin;
list.Condition = body.Members.OfType <ReferenceMemberFragment>().Select(member =>
{
var left = list.Members.OfType <ReferenceMemberFragment>().Where(a => a.Reference == member.Reference).Single();
return(new BinaryFragment(context, EBinaryKind.Equal)
{
Left = left,
Right = ValidateMember(context, member, container, null, true)
});
}).Merge();
return(list);
}
/// <summary>
/// 根据指定类型<see cref="DbCollectionMemberExpression"/>表达式创建虚拟数据源列表语句片段。
/// </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 CreateVirtualListForCollectionMember(GenerateContext context, VirtualSourceFragment source)
{
var content = (DbCollectionMemberExpression)source.Expression;
var target = GetSource(context, content.TargetSet.Item);
var container = source.Container;
if (container.IsRecommandLock)
{
container = container.Parent as SelectFragment;
}
var list = new SelectFragment(context, target);
if (content.Metadata.IsComposite)
{
GenerateVirtualCompositeJoinForCollectionMember(context, content, list, true);
}
container.AddSource(list);
GenerateVirtualJoinForCollectionMember(context, source, list, false);
list.RetrievalMembers(content.TargetSet.Item, false);
if (IsSelectFragment(content))
{
context.RegisterTempSource(content.Item, target, delegate()
{
list = InitialSelectFragment(list, content);
});
}
return(list);
}
/// <summary>
/// 根据指定类型<see cref="DbGroupJoinExpression"/>表达式创建虚拟数据源列表语句片段。
/// </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 CreateVirtualListForGroupJoin(GenerateContext context, VirtualSourceFragment source)
{
var content = (DbGroupJoinExpression)source.Expression;
var target = GetSource(context, content.Target.Item);
var list = new SelectFragment(context, target);
var container = source.Container;
if (container.IsRecommandLock)
{
container = container.Parent as SelectFragment;
}
container.AddSource(list);
list.Join = EJoinType.LeftJoin;
list.Condition = content.KeyPairs.Select(a => container.CreateExpression(a)).Merge();
list.RetrievalMembers(content.Target.Item, false);
return(list);
}
/// <summary>
/// 根据指定类型<see cref="DbGroupByExpression"/>表达式创建数据源语句片段。
/// </summary>
/// <param name="context">生成上下文。</param>
/// <param name="expression">指定表达式。</param>
/// <returns>创建结果。</returns>
protected virtual ISourceFragment CreateSourceForGroupBy(GenerateContext context, DbExpression expression)
{
var content = (DbGroupByExpression)expression;
var groupitem = (DbGroupItemExpression)content.Item;
var source = CreateSource(context, content.Source);
var body = new SelectFragment(context, source);
body.RetrievalMembers(content.Key, false);
foreach (var member in body.Members.OfType <ReferenceMemberFragment>())
{
body.GroupBys.Add(member.Reference);
}
var container = new SelectFragment(context, body);
var virtualSource = new VirtualSourceFragment(context, expression, container, source, body);
context.RegisterSource(content, virtualSource);
context.RegisterSource(content.Item, virtualSource);
return(container);
}