//p=>p
//p=>p.t
//p=>p.Id
protected override Expression VisitLambda <T>(Expression <T> node)
{
LambdaExpression lambda = node as LambdaExpression;
if (lambda.Body.NodeType == ExpressionType.Parameter)
{
// expression like a=> a
Type type = lambda.Body.Type;
string alias = _aliases.GetTableAlias(lambda);
this.VisitAllMember(type, alias);
return(node);
}
if (lambda.Body.NodeType == ExpressionType.MemberAccess)
{
// expression like t=> t.a
// => SELECT a.ClientId
Type type = lambda.Body.Type;
return(TypeUtils.IsPrimitive(type)
? base.VisitLambda(node)
: this.VisitAllMember(type, _aliases.GetTableAlias(lambda.Body), node));
}
if (_mOnly)
{
_mOnly = false;
}
return(base.VisitLambda(node));
}
// 获取 LEFT JOIN / INNER JOIN 子句关联表的的别名
private void GetLfInJoinAlias(DbExpression exp, TableAliasCache aliases)
{
Type type = exp.Expressions[0].Type.GetGenericArguments()[0];
string name = TypeRuntimeInfoCache.GetRuntimeInfo(type).TableName;
// on a.Name equals b.Name 或 on new{ Name = a.Name,Id=a.Id } equals new { Name = b.Name,Id=b.Id }
LambdaExpression left = exp.Expressions[1] as LambdaExpression;
LambdaExpression right = exp.Expressions[2] as LambdaExpression;
NewExpression body1 = left.Body as NewExpression;
if (body1 == null)
{
aliases.GetTableAlias(exp.Expressions[1]);
string alias = aliases.GetTableAlias(exp.Expressions[2]);
// 记录显示指定的LEFT JOIN 表别名
aliases.AddOrUpdateJoinTableAlias(name, alias);
}
else
{
NewExpression body2 = right.Body as NewExpression;
for (int index = 0; index < body1.Arguments.Count; ++index)
{
aliases.GetTableAlias(body1.Arguments[index]);
string alias = aliases.GetTableAlias(body2.Arguments[index]);
// 记录显示指定的LEFT JOIN 表别名
aliases.AddOrUpdateJoinTableAlias(name, alias);
}
}
}
// LEFT OR INNER JOIN
private void AppendLfInJoin(SqlBuilder builder, DbExpression exp, TableAliasCache aliases)
{
// [TableName]
//var constExp = exp.Expressions[0] as ConstantExpression;
//constExp.Type.GetGenericArguments()[0]
//var queryable = constExp.Value as IDbQueryable;
//var innerExp = queryable.DbExpressions[0];
//if (innerExp.DbExpressionType != DbExpressionType.GetTable) throw new XfwException("inner expression must be GetTable<T> expression");
//Type type = (innerExp.Expression as ConstantExpression).Value as Type;
Type type = exp.Expressions[0].Type.GetGenericArguments()[0];
builder.Append(' ');
builder.AppendMember(TypeRuntimeInfoCache.GetRuntimeInfo(type).TableName);
LambdaExpression left = exp.Expressions[1] as LambdaExpression;
LambdaExpression right = exp.Expressions[2] as LambdaExpression;
NewExpression body1 = left.Body as NewExpression;
NewExpression body2 = right.Body as NewExpression;
// t0(t1)
string alias = body1 == null
? aliases.GetTableAlias(exp.Expressions[2])
: aliases.GetTableAlias(body2.Arguments[0]);
builder.Append(' ');
builder.Append(alias);
builder.Append(' ');
// ON a.Name = b.Name AND a.Id = b.Id
builder.Append("ON ");
if (body1 == null)
{
builder.AppendMember(aliases, left.Body.ReduceUnary());
builder.Append(" = ");
builder.AppendMember(aliases, right.Body.ReduceUnary());
}
else
{
for (int index = 0; index < body1.Arguments.Count; ++index)
{
builder.AppendMember(aliases, body1.Arguments[index]);
builder.Append(" = ");
builder.AppendMember(aliases, body2.Arguments[index]);
if (index < body1.Arguments.Count - 1)
{
builder.Append(" AND ");
}
}
}
}
/// <summary>
/// 追加列名
/// </summary>
/// <param name="aliases">表别名</param>
/// <param name="expression">列名表达式</param>
/// <returns>返回解析到的表别名</returns>
public string AppendMember(TableAliasCache aliases, Expression expression)
{
Expression exp = expression;
LambdaExpression lambdaExpression = exp as LambdaExpression;
if (lambdaExpression != null)
{
exp = lambdaExpression.Body;
}
MemberExpression memExp = exp as MemberExpression;
if (expression.NodeType == ExpressionType.Constant || memExp.Expression.NodeType == ExpressionType.Constant)
{
PartialVisitor visitor = new PartialVisitor();
var eval = visitor.Eval(memExp ?? expression);
string value = eval.NodeType == ExpressionType.Constant
? ExpressionVisitorBase.GetSqlValue((eval as ConstantExpression).Value)
: string.Empty;
_builder.Append(value);
return(value);
}
else
{
string alias = aliases == null ? null : aliases.GetTableAlias(memExp);
this.AppendMember(alias, memExp.Member.Name);
return(alias);
}
}
// 获取 CROSS JOIN 子句关联表的的别名
private void GetCrossJoinAlias(DbExpression exp, TableAliasCache aliases)
{
LambdaExpression lambdaExp = exp.Expressions[1] as LambdaExpression;
for (int index = 0; index < lambdaExp.Parameters.Count; ++index)
{
aliases.GetTableAlias(lambdaExp.Parameters[index]);
}
}
// Cross Join
private void AppendCrossJoin(SqlBuilder builder, DbExpression exp, TableAliasCache aliases)
{
LambdaExpression lambdaExp = exp.Expressions[1] as LambdaExpression;
Type type = lambdaExp.Parameters[1].Type;
builder.Append(' ');
builder.AppendMember(TypeRuntimeInfoCache.GetRuntimeInfo(type).TableName);
string alias = aliases.GetTableAlias(lambdaExp.Parameters[1]);
builder.Append(' ');
builder.Append(alias);
builder.Append(' ');
}
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 ");
}
}
}
}
