protected virtual void VisitNavigation(Expression node, string memberName = null)
{
// 表达式 => b.Client.Address.AddressName
Expression f = node;
Stack <KeyValuePair <string, MemberExpression> > stack = null;
while (f != null && f.IsVisitable())
{
if (f.NodeType != ExpressionType.MemberAccess)
{
break;
}
if (stack == null)
{
stack = new Stack <KeyValuePair <string, MemberExpression> >();
}
MemberExpression m = f as MemberExpression;
var runtime = TypeRuntimeInfoCache.GetRuntimeInfo(m.Expression.Type);
ForeignKeyAttribute attribute = runtime.GetWrapperAttribute <ForeignKeyAttribute>(m.Member.Name);
if (attribute == null)
{
break;
}
string key = m.GetKeyWidthoutAnonymous();
stack.Push(new KeyValuePair <string, MemberExpression>(key, m));
f = m.Expression;
}
if (stack != null && stack.Count > 0)
{
while (stack != null && stack.Count > 0)
{
KeyValuePair <string, MemberExpression> kvp = stack.Pop();
string key = kvp.Key;
MemberExpression m = kvp.Value;
var runtime = TypeRuntimeInfoCache.GetRuntimeInfo(m.Type);
// 检查查询表达式是否显示指定该表关联
string alias = _aliases.GetJoinTableAlias(runtime.TableName);
if (string.IsNullOrEmpty(alias))
{
// 如果没有，则使用导航属性别名
alias = _aliases.GetNavigationTableAlias(key);
if (!_navigations.ContainsKey(kvp.Key))
{
_navigations.Add(kvp);
}
}
if (stack.Count == 0 && !string.IsNullOrEmpty(memberName))
{
_builder.AppendMember(alias, memberName);
}
}
}
else
{
// => SelectMany 也会产生类似 'b.Client.Address.AddressName' 这样的表达式
string alias = _aliases.GetTableAlias(node);
_builder.AppendMember(alias, memberName);
}
//return f;
}
// 添加导航属性关联
protected virtual void AppendNavigation()
{
if (this.AdditionForeigns == null || this.AdditionForeigns.Count == 0)
{
return;
}
//开始产生LEFT JOIN 子句
SqlBuilder builder = this.JoinFragment;
foreach (var kvp in _navigations)
{
string key = kvp.Key;
MemberExpression m = kvp.Value;
var runtime = TypeRuntimeInfoCache.GetRuntimeInfo(m.Expression.Type);
ForeignKeyAttribute attribute = runtime.GetWrapperAttribute <ForeignKeyAttribute>(m.Member.Name);
string innerKey = string.Empty;
string outerKey = key;
string innerAlias = string.Empty;
if (!m.Expression.IsVisitable())
{
innerKey = m.Expression.NodeType == ExpressionType.Parameter
? (m.Expression as ParameterExpression).Name
: (m.Expression as MemberExpression).Member.Name;
}
else
{
MemberExpression mLeft = m.Expression as MemberExpression;
string name = TypeRuntimeInfoCache.GetRuntimeInfo(mLeft.Type).TableName;
innerAlias = _aliases.GetJoinTableAlias(name);
if (string.IsNullOrEmpty(innerAlias))
{
string keyLeft = mLeft.GetKeyWidthoutAnonymous();
if (_navigations.ContainsKey(keyLeft))
{
innerKey = keyLeft;
}
}
}
string alias1 = !string.IsNullOrEmpty(innerAlias) ? innerAlias : _aliases.GetTableAlias(innerKey);
string alias2 = _aliases.GetTableAlias(outerKey);
builder.AppendNewLine();
builder.Append("LEFT JOIN ");
Type pType = m.Type;
//不实现一对多映射
//if (pType.IsGenericType) pType = pType.GetGenericArguments()[0];
builder.AppendMember(TypeRuntimeInfoCache.GetRuntimeInfo(pType).TableName);
builder.Append(" ");
builder.Append(alias2);
builder.Append(" ON ");
for (int i = 0; i < attribute.InnerKeys.Length; i++)
{
builder.Append(alias1);
builder.Append('.');
builder.AppendMember(attribute.InnerKeys[i]);
builder.Append(" = ");
builder.Append(alias2);
builder.Append('.');
builder.AppendMember(attribute.OuterKeys[i]);
if (i < attribute.InnerKeys.Length - 1)
{
builder.Append(" AND ");
}
}
}
}
