/// <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);
}
}
//private string GetSqlValue(string value, MemberExpression node = null)
//{
// if (value == null) return "NULL";
// MemberExpression memberExp = node;
// // make sure always visit ConstantExpression Last *******
// //if (memberExp == null)
// //{
// // while (_stcMember.Count > 0)
// // {
// // var temp = _stcMember.Pop();
// // if (memberExp == null) memberExp = temp;
// // }
// //}
// //bool isNv = true;
// //if (memberExp != null)
// //{
// // //DbType from memberInfo
// // var rInfo = TypeRuntimeInfoCache.GetRuntimeInfo(memberExp.Member.DeclaringType);
// // var wrapper = rInfo.GetWrapper(memberExp.Member.Name) as MemberAccessWrapper;
// // if (wrapper != null && wrapper.Column != null)
// // {
// // isNv = wrapper.Column.DbType == DbType.String || wrapper.Column.DbType == DbType.StringFixedLength;
// // }
// //}
// //// N'信息科技' 或者 'Google'
// //return string.Format("{0}'{1}'", isNv ? "N" : string.Empty, value.ToString().Replace("'", "''"));
//}
private static string GetSqlValue(IEnumerable value, MemberExpression node = null)
{
if (value == null)
{
return("NULL");
}
MemberExpression memberExp = node;
var iterator = value.GetEnumerator();
List <string> stack = new List <string>();
while (iterator.MoveNext())
{
stack.Add(ExpressionVisitorBase.GetSqlValue(iterator.Current, memberExp));
}
// =>a,b,c
string sql = string.Join(",", stack);
return(sql);
}
/// <summary>
/// 取值对应的sql片断
/// </summary>
public static string GetSqlValue(object value, MemberExpression node = null)
{
if (value == null)
{
return("NULL");
}
Type type = value.GetType();
if (type == typeof(string))
{
return(string.Format("N'{0}'", value.ToString().Replace("'", "''")));
}
//return this.GetSqlValue(value as string, node);
if (type == typeof(Guid))
{
return(string.Format("'{0}'", value));
}
if (type == typeof(DateTime))
{
return(string.Format("'{0}'", value));
}
if (type == typeof(bool))
{
return(Convert.ToBoolean(value) ? "1" : "0");
}
if (typeof(IEnumerable).IsAssignableFrom(type))
{
return(ExpressionVisitorBase.GetSqlValue(value as IEnumerable, node));
}
return(value.ToString());
}
/// <summary> /// 获取 Length 属性对应的SQL函数 /// </summary> /// <param name="node">字段或者属性节点</param> /// <param name="visitorBase">访问器</param> /// <returns></returns> public abstract string GetLenFuncName(MemberExpression node, ExpressionVisitorBase visitor);
/// <summary> /// 访问表示字段或者属性的属性的节点 a.Name.Length /// </summary> /// <param name="node">字段或者属性节点</param> /// <param name="visitorBase">访问器</param> /// <returns></returns> public abstract Expression VisitMemberMember(MemberExpression node, ExpressionVisitorBase visitor);
/// <summary> /// 访问表示 null 合并运算的节点 a ?? b /// </summary> /// <param name="b">二元表达式节点</param> /// <param name="visitorBase">访问器</param> /// <returns></returns> public abstract Expression VisitCoalesce(BinaryExpression b, ExpressionVisitorBase visitor);
/// <summary> /// 访问表示 null 判断运算的节点 a.Name == null /// </summary> /// <param name="b">二元表达式节点</param> /// <param name="visitorBase">访问器</param> /// <returns></returns> public abstract Expression VisitEqualNull(BinaryExpression b, ExpressionVisitorBase visitor);
/// <summary> /// 访问表示方法调用的节点 /// </summary> /// <param name="node">方法调用节点</param> /// <param name="visitorBase">访问器</param> /// <returns></returns> public abstract Expression VisitMethodCall(MethodCallExpression node, ExpressionVisitorBase visitor);
