Ejemplo n.º 1
0
        //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)
            {
                // 例: a=> a
                Type   type  = lambda.Body.Type;
                string alias = _aliases.GetTableAlias(lambda);
                this.VisitAllMember(type, alias);
                return(node);
            }
            else if (lambda.Body.CanEvaluate())
            {
                // 例:a=>1
                base.Visit(lambda.Body.Evaluate());

                // 选择字段
                string newName = AddColumn(_columns, "__Constant__");
                // 添加字段别名
                _builder.AppendAs(newName);
                return(node);
            }
            else if (lambda.Body.NodeType == ExpressionType.MemberAccess)
            {
                // 例: t=> t.a
                // => SELECT a.ClientId
                Type type = lambda.Body.Type;
                return(TypeUtils.IsPrimitiveType(type)
                    ? base.VisitLambda(node)
                    : this.VisitAllMember(type, _aliases.GetTableAlias(lambda.Body), node));
            }

            return(base.VisitLambda(node));
        }
        // 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)
            {
                // 例: a=> a
                Type   type  = lambda.Body.Type;
                string alias = _aliases.GetTableAlias(lambda);
                this.VisitAllMember(type, alias);
                return(node);
            }
            else if (lambda.Body.CanEvaluate())
            {
                // 例:a=>1
                base.Visit(lambda.Body.Evaluate());
                // 选择字段
                string newName = _pickColumns.Add(Constant.CONSTANTNAME);
                // 添加字段别名
                _builder.AppendAs(newName);
                return(node);
            }
            else if (lambda.Body.NodeType == ExpressionType.MemberAccess)
            {
                // 例: t=> t.a
                // => SELECT a.ClientId
                Type type = lambda.Body.Type;
                if (!TypeUtils.IsPrimitiveType(type))
                {
                    return(this.VisitAllMember(type, _aliases.GetTableAlias(lambda.Body), node));
                }
                else
                {
                    var    newNode = this.VisitWithoutRemark(x => base.VisitLambda(node));
                    string newName = _pickColumns.Add((lambda.Body as MemberExpression).Member.Name);
                    return(newNode);
                }
            }
            else
            {
                var newNode = base.VisitLambda(node);
                if (_pickColumns.Count == 0)
                {
                    // 选择字段
                    string newName = _pickColumns.Add(Constant.CONSTANTNAME);
                    // 添加字段别名
                    _builder.AppendAs(newName);
                }
                return(newNode);
            }
        }
Ejemplo n.º 3
0
        /// <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;
            }

            if (expression.CanEvaluate())
            {
                ConstantExpression c     = expression.Evaluate();
                string             value = this.GetSqlValue(c.Value);
                _innerBuilder.Append(value);
                return(value);
            }
            else
            {
                MemberExpression m     = expression as MemberExpression;
                string           alias = aliases == null ? null : aliases.GetTableAlias(m);
                this.AppendMember(alias, m.Member.Name);
                return(alias);
            }
        }
Ejemplo n.º 4
0
        // Cross Join
        private void AppendCrossJoin(ISqlBuilder jf, DbExpression dbExpression, TableAliasCache aliases)
        {
            if (!usedKeyword)
            {
                jf.AppendNewLine();
                jf.Append(_keywordName);
                usedKeyword = true;
            }
            else
            {
                jf.Append(',');
                jf.AppendNewLine();
                jf.Append(_pad);
            }

            LambdaExpression lambda = dbExpression.Expressions[1] as LambdaExpression;
            Type             type   = lambda.Parameters[1].Type;
            var typeRuntime         = TypeRuntimeInfoCache.GetRuntimeInfo(type);

            jf.AppendMember(typeRuntime.TableName, !typeRuntime.IsTemporary);

            string alias = aliases.GetTableAlias(lambda.Parameters[1]);

            jf.Append(' ');
            jf.Append(alias);
        }
Ejemplo n.º 5
0
        // 获取 CROSS JOIN 子句关联表的的别名
        private void PrepareCrossJoinAlias(DbExpression dbExpression, TableAliasCache aliases)
        {
            LambdaExpression lambdaExp = dbExpression.Expressions[1] as LambdaExpression;

            for (int index = 0; index < lambdaExp.Parameters.Count; ++index)
            {
                aliases.GetTableAlias(lambdaExp.Parameters[index]);
            }
        }
Ejemplo n.º 6
0
        // Cross Join
        private void AppendCrossJoin(ISqlBuilder builder, DbExpression exp, TableAliasCache aliases)
        {
            LambdaExpression lambdaExp = exp.Expressions[1] as LambdaExpression;
            Type             type      = lambdaExp.Parameters[1].Type;
            var typeRuntime            = TypeRuntimeInfoCache.GetRuntimeInfo(type);

            builder.Append(' ');
            builder.AppendMember(typeRuntime.TableName, !typeRuntime.IsTemporary);

            string alias = aliases.GetTableAlias(lambdaExp.Parameters[1]);

            builder.Append(' ');
            builder.Append(alias);
            builder.Append(' ');
        }
Ejemplo n.º 7
0
        //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)
            {
                // 例: a=> a
                Type   type  = lambda.Body.Type;
                string alias = _aliases.GetTableAlias(lambda);
                this.VisitAllMember(type, alias);
                return(node);
            }
            else if (lambda.Body.CanEvaluate())
            {
                // 例:a=>1
                base.Visit(lambda.Body.Evaluate());

                // 选择字段
                string newName = AddColumn(_columns, "__Constant__", null);
                // 添加字段别名
                _builder.AppendAs(newName);
                return(node);
            }
            else if (lambda.Body.NodeType == ExpressionType.MemberAccess)
            {
                // 例: t=> t.a
                // => SELECT a.ClientId
                Type type = lambda.Body.Type;
                if (!TypeUtils.IsPrimitiveType(type))
                {
                    return(this.VisitAllMember(type, _aliases.GetTableAlias(lambda.Body), node));
                }
                else
                {
                    var    newNode = base.VisitLambda(node);
                    string alias   = _visitedMark.Current != null?_aliases.GetTableAlias(_visitedMark.Current) : null;

                    string newName = AddColumn(_columns, (lambda.Body as MemberExpression).Member.Name, alias);
                    //_builder.AppendAs(newName);
                    //_builder.Append(',');
                    //_builder.AppendNewLine();
                    return(newNode);
                }
            }
            else
            {
                return(base.VisitLambda(node));
            }
        }
Ejemplo n.º 8
0
        // 获取 LEFT JOIN / INNER JOIN 子句关联表的的别名
        private void PrepareLfInJoinAlias(DbExpression dbExpression, TableAliasCache aliases)
        {
            Type   type = dbExpression.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  = dbExpression.Expressions[1] as LambdaExpression;
            LambdaExpression right = dbExpression.Expressions[2] as LambdaExpression;

            if (left.Body.NodeType == ExpressionType.New)
            {
                NewExpression body1 = left.Body as NewExpression;
                NewExpression body2 = right.Body as NewExpression;
                for (int index = 0; index < body1.Arguments.Count; ++index)
                {
                    aliases.GetTableAlias(body1.Arguments[index]);
                }
                for (int index = 0; index < body2.Arguments.Count; ++index)
                {
                    string alias = aliases.GetTableAlias(body2.Arguments[index]);
                    // 记录显示指定的LEFT JOIN 表别名
                    aliases.AddOrUpdateJoinTableAlias(name, alias);
                }
            }
            else if (left.Body.NodeType == ExpressionType.MemberInit)
            {
                MemberInitExpression body1 = left.Body as MemberInitExpression;
                MemberInitExpression body2 = right.Body as MemberInitExpression;
                for (int index = 0; index < body1.Bindings.Count; ++index)
                {
                    aliases.GetTableAlias((body1.Bindings[index] as MemberAssignment).Expression);
                }
                for (int index = 0; index < body2.Bindings.Count; ++index)
                {
                    string alias = aliases.GetTableAlias((body2.Bindings[index] as MemberAssignment).Expression);
                    // 记录显示指定的LEFT JOIN 表别名
                    aliases.AddOrUpdateJoinTableAlias(name, alias);
                }
            }
            else
            {
                aliases.GetTableAlias(dbExpression.Expressions[1]);
                string alias = aliases.GetTableAlias(dbExpression.Expressions[2]);
                // 记录显示指定的LEFT JOIN 表别名
                aliases.AddOrUpdateJoinTableAlias(name, alias);
            }
        }
Ejemplo n.º 9
0
        // 添加导航属性关联
        protected virtual void AppendNavigation()
        {
            if (this._navMembers == null || this._navMembers.Count == 0)
            {
                return;
            }

            // 如果有一对多的导航属性,肯定会产生嵌套查询。那么内层查询别名肯定是t0,所以需要清掉
            if (this.HasManyNavigation)
            {
                _aliases = new TableAliasCache(_aliases.Declared);
            }
            //开始产生LEFT JOIN 子句
            ISqlBuilder builder = this.JoinFragment;

            foreach (var kvp in _navMembers)
            {
                string              key         = kvp.Key;
                MemberExpression    m           = kvp.Value;
                TypeRuntimeInfo     typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(m.Expression.Type);
                ForeignKeyAttribute attribute   = typeRuntime.GetInvokerAttribute <ForeignKeyAttribute>(m.Member.Name);

                string innerKey   = string.Empty;
                string outerKey   = key;
                string innerAlias = string.Empty;

                if (!m.Expression.Acceptable())
                {
                    innerKey = m.Expression.NodeType == ExpressionType.Parameter
                        ? (m.Expression as ParameterExpression).Name
                        : (m.Expression as MemberExpression).Member.Name;
                }
                else
                {
                    MemberExpression mLeft = null;
                    if (m.Expression.NodeType == ExpressionType.MemberAccess)
                    {
                        mLeft = m.Expression as MemberExpression;
                    }
                    else if (m.Expression.NodeType == ExpressionType.Call)
                    {
                        mLeft = (m.Expression as MethodCallExpression).Object as MemberExpression;
                    }
                    string name = TypeRuntimeInfoCache.GetRuntimeInfo(mLeft.Type).TableName;
                    innerAlias = _aliases.GetJoinTableAlias(name);

                    if (string.IsNullOrEmpty(innerAlias))
                    {
                        string keyLeft = mLeft.GetKeyWidthoutAnonymous();
                        if (_navMembers.ContainsKey(keyLeft))
                        {
                            innerKey = keyLeft;
                        }
                        innerAlias = _aliases.GetNavigationTableAlias(innerKey);
                    }
                }

                string alias1 = !string.IsNullOrEmpty(innerAlias) ? innerAlias : _aliases.GetTableAlias(innerKey);
                string alias2 = _aliases.GetNavigationTableAlias(outerKey);


                builder.AppendNewLine();
                builder.Append("LEFT JOIN ");
                Type type = m.Type;
                if (type.IsGenericType)
                {
                    type = type.GetGenericArguments()[0];
                }
                var typeRuntime2 = TypeRuntimeInfoCache.GetRuntimeInfo(type);
                builder.AppendMember(typeRuntime2.TableName, !typeRuntime2.IsTemporary);
                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 ");
                    }
                }
            }
        }
Ejemplo n.º 10
0
        // LEFT OR INNER JOIN
        private void AppendLfInJoin(ISqlBuilder builder, DbExpression dbExpression, TableAliasCache aliases)
        {
            builder.Append(' ');
            IDbQueryable sQuery = (IDbQueryable)((dbExpression.Expressions[0] as ConstantExpression).Value);

            if (sQuery.DbExpressions.Count == 1 && sQuery.DbExpressions[0].DbExpressionType == DbExpressionType.GetTable)
            {
                Type type        = dbExpression.Expressions[0].Type.GetGenericArguments()[0];
                var  typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(type);
                builder.AppendMember(typeRuntime.TableName, !typeRuntime.IsTemporary);
            }
            else
            {
                // 嵌套
                var cmd = sQuery.Resolve(builder.Indent + 1, false, builder.Token);
                builder.Append("(");
                builder.Append(cmd.CommandText);
                builder.AppendNewLine();
                builder.Append(')');
            }


            LambdaExpression left  = dbExpression.Expressions[1] as LambdaExpression;
            LambdaExpression right = dbExpression.Expressions[2] as LambdaExpression;

            // t0(t1)
            string alias = !(left.Body.NodeType == ExpressionType.New || left.Body.NodeType == ExpressionType.MemberInit)
                ? aliases.GetTableAlias(dbExpression.Expressions[2])
                : aliases.GetTableAlias(right.Parameters[0]);

            builder.Append(' ');
            builder.Append(alias);
            builder.Append(' ');

            // ON a.Name = b.Name AND a.Id = b.Id
            builder.Append("ON ");

            if (left.Body.NodeType == ExpressionType.New)
            {
                NewExpression body1 = left.Body as NewExpression;
                NewExpression body2 = right.Body as NewExpression;

                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 ");
                    }
                }
            }
            else if (left.Body.NodeType == ExpressionType.MemberInit)
            {
                MemberInitExpression body1 = left.Body as MemberInitExpression;
                MemberInitExpression body2 = right.Body as MemberInitExpression;

                for (int index = 0; index < body1.Bindings.Count; ++index)
                {
                    builder.AppendMember(aliases, (body1.Bindings[index] as MemberAssignment).Expression);
                    builder.Append(" = ");
                    builder.AppendMember(aliases, (body2.Bindings[index] as MemberAssignment).Expression);
                    if (index < body1.Bindings.Count - 1)
                    {
                        builder.Append(" AND ");
                    }
                }
            }
            else
            {
                builder.AppendMember(aliases, left.Body.ReduceUnary());
                builder.Append(" = ");
                builder.AppendMember(aliases, right.Body.ReduceUnary());
            }
        }
Ejemplo n.º 11
0
        // 添加导航属性关联
        protected override void AppendNavigation()
        {
            if (this.NavMembers == null || this.NavMembers.Count == 0)
            {
                return;
            }

            // 如果有一对多的导航属性,肯定会产生嵌套查询。那么内层查询别名肯定是t0,所以需要清掉
            if (this.HasMany)
            {
                _aliases = new TableAliasCache(_aliases.Declared);
            }
            //开始产生 USING 子句
            ISqlBuilder jf    = this.JoinFragment;
            int         index = -1;

            // 未生成USING子句
            if (_aliases.Declared <= 1)
            {
                jf.AppendNewLine();
                jf.Append(_keywordName);
            }
            else
            {
                jf.Append(',');
                jf.AppendNewLine();
            }

            foreach (var kvp in this.NavMembers)
            {
                index++;
                string              key         = kvp.Key;
                MemberExpression    m           = kvp.Value;
                TypeRuntimeInfo     typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(m.Expression.Type);
                ForeignKeyAttribute attribute   = typeRuntime.GetInvokerAttribute <ForeignKeyAttribute>(m.Member.Name);

                string innerKey   = string.Empty;
                string outerKey   = key;
                string innerAlias = string.Empty;

                if (!m.Expression.Acceptable())
                {
                    innerKey = m.Expression.NodeType == ExpressionType.Parameter
                        ? (m.Expression as ParameterExpression).Name
                        : (m.Expression as MemberExpression).Member.Name;
                }
                else
                {
                    MemberExpression mLeft = null;
                    if (m.Expression.NodeType == ExpressionType.MemberAccess)
                    {
                        mLeft = m.Expression as MemberExpression;
                    }
                    else if (m.Expression.NodeType == ExpressionType.Call)
                    {
                        mLeft = (m.Expression as MethodCallExpression).Object as MemberExpression;
                    }
                    string name = TypeRuntimeInfoCache.GetRuntimeInfo(mLeft.Type).TableName;
                    innerAlias = _aliases.GetJoinTableAlias(name);

                    if (string.IsNullOrEmpty(innerAlias))
                    {
                        string keyLeft = mLeft.GetKeyWidthoutAnonymous();
                        if (this.NavMembers.ContainsKey(keyLeft))
                        {
                            innerKey = keyLeft;
                        }
                        innerAlias = _aliases.GetNavigationTableAlias(innerKey);
                    }
                }

                string alias1 = !string.IsNullOrEmpty(innerAlias) ? innerAlias : _aliases.GetTableAlias(innerKey);
                string alias2 = _aliases.GetNavigationTableAlias(outerKey);

                // 补充与USING字符串同等间距的空白
                if (_aliases.Declared > 1 || index > 0)
                {
                    jf.Append(_pad);
                }

                Type type         = m.Type;
                var  typeRumtime2 = TypeRuntimeInfoCache.GetRuntimeInfo(type);
                if (type.IsGenericType)
                {
                    type = type.GetGenericArguments()[0];
                }
                jf.AppendMember(typeRumtime2.TableName, typeRumtime2.IsTemporary);
                jf.Append(' ');
                jf.Append(alias2);

                if (_onPhrase.Length > 0)
                {
                    _onPhrase.Append(" AND ");
                }
                for (int i = 0; i < attribute.InnerKeys.Length; i++)
                {
                    _onPhrase.Append(alias1);
                    _onPhrase.Append('.');
                    _onPhrase.AppendMember(attribute.InnerKeys[i]);
                    _onPhrase.Append(" = ");
                    _onPhrase.Append(alias2);
                    _onPhrase.Append('.');
                    _onPhrase.AppendMember(attribute.OuterKeys[i]);
                }

                if (index < this.NavMembers.Count - 1)
                {
                    jf.Append(',');
                    jf.AppendNewLine();
                }
            }
        }
Ejemplo n.º 12
0
        // LEFT OR INNER JOIN
        private void AppendLfInJoin(ISqlBuilder jf, ISqlBuilder on, DbExpression dbExpression, TableAliasCache aliases)
        {
            IDbQueryable sQuery = (IDbQueryable)((dbExpression.Expressions[0] as ConstantExpression).Value);

            if (!usedKeyword)
            {
                jf.AppendNewLine();
                jf.Append(_keywordName);
                usedKeyword = true;
            }
            else
            {
                jf.Append(',');
                jf.AppendNewLine();
                jf.Append(_pad);
            }

            if (sQuery.DbExpressions.Count == 1 && sQuery.DbExpressions[0].DbExpressionType == DbExpressionType.GetTable)
            {
                Type type        = dbExpression.Expressions[0].Type.GetGenericArguments()[0];
                var  typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(type);
                jf.AppendMember(typeRuntime.TableName, !typeRuntime.IsTemporary);
            }
            else
            {
                // 嵌套
                var cmd = sQuery.Resolve(jf.Indent + _dbExpressionType == DbExpressionType.Delete ? 2 : 1, false, jf.Token);
                jf.Append("( ");
                jf.Append(_dbExpressionType == DbExpressionType.Delete ? cmd.CommandText.TrimStart() : cmd.CommandText);
                jf.Append(')');
            }

            LambdaExpression left  = dbExpression.Expressions[1] as LambdaExpression;
            LambdaExpression right = dbExpression.Expressions[2] as LambdaExpression;

            // t0(t1)
            string alias = !(left.Body.NodeType == ExpressionType.New || left.Body.NodeType == ExpressionType.MemberInit)
                ? aliases.GetTableAlias(dbExpression.Expressions[2])
                : aliases.GetTableAlias(right.Parameters[0]);

            jf.Append(' ');
            jf.Append(alias);

            if (on.Length > 0)
            {
                on.Append(" AND ");
            }

            if (left.Body.NodeType == ExpressionType.New)
            {
                NewExpression body1 = left.Body as NewExpression;
                NewExpression body2 = right.Body as NewExpression;

                for (int index = 0; index < body1.Arguments.Count; ++index)
                {
                    on.AppendMember(aliases, body1.Arguments[index]);
                    on.Append(" = ");
                    on.AppendMember(aliases, body2.Arguments[index]);
                    if (index < body1.Arguments.Count - 1)
                    {
                        on.Append(" AND ");
                    }
                }
            }
            else if (left.Body.NodeType == ExpressionType.MemberInit)
            {
                MemberInitExpression body1 = left.Body as MemberInitExpression;
                MemberInitExpression body2 = right.Body as MemberInitExpression;

                for (int index = 0; index < body1.Bindings.Count; ++index)
                {
                    on.AppendMember(aliases, (body1.Bindings[index] as MemberAssignment).Expression);
                    on.Append(" = ");
                    on.AppendMember(aliases, (body2.Bindings[index] as MemberAssignment).Expression);
                    if (index < body1.Bindings.Count - 1)
                    {
                        on.Append(" AND ");
                    }
                }
            }
            else
            {
                on.AppendMember(aliases, left.Body.ReduceUnary());
                on.Append(" = ");
                on.AppendMember(aliases, right.Body.ReduceUnary());
            }
        }
Ejemplo n.º 13
0
        // 访问导航属性
        protected virtual string VisitNavMember(Expression expression, string memberName = null)
        {
            // 表达式 => b.Client.Address.AddressName
            Expression node = expression;
            Stack <KeyValuePair <string, MemberExpression> > stack = null;
            string alias = string.Empty;

            while (node != null && node.Acceptable())
            {
                if (node.NodeType != ExpressionType.MemberAccess)
                {
                    break;
                }

                if (stack == null)
                {
                    stack = new Stack <KeyValuePair <string, MemberExpression> >();
                }
                MemberExpression memberExpression = node as MemberExpression;

                TypeRuntimeInfo     typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(memberExpression.Expression.Type);
                ForeignKeyAttribute attribute   = typeRuntime.GetInvokerAttribute <ForeignKeyAttribute>(memberExpression.Member.Name);
                if (attribute == null)
                {
                    break;
                }

                string key = memberExpression.GetKeyWidthoutAnonymous();
                stack.Push(new KeyValuePair <string, MemberExpression>(key, memberExpression));
                node = memberExpression.Expression;
                if (node.NodeType == ExpressionType.Call)
                {
                    node = (node as MethodCallExpression).Object;
                }
            }

            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;
                    Type             type = m.Type;
                    if (type.IsGenericType)
                    {
                        type = type.GetGenericArguments()[0];
                    }

                    TypeRuntimeInfo typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(type);
                    // 检查查询表达式是否显示指定该表关联
                    alias = _aliases.GetJoinTableAlias(typeRuntime.TableName);
                    if (string.IsNullOrEmpty(alias))
                    {
                        // 如果没有,则使用导航属性别名
                        alias = _aliases.GetNavigationTableAlias(key);
                        if (!_navMembers.ContainsKey(kvp.Key))
                        {
                            _navMembers.Add(kvp);
                        }
                    }

                    // 例: a.Client.ClientId
                    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
                alias = _aliases.GetTableAlias(expression);
                _builder.AppendMember(alias, memberName);
            }

            // fix issue# Join 表达式显式指定导航属性时时,alias 为空
            return(alias);
        }
        // LEFT OR INNER JOIN
        private void AppendLfInJoin(ISqlBuilder jf, ISqlBuilder wf, ISqlBuilder on, DbExpression exp, TableAliasCache aliases)
        {
            bool             useExists = false;
            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(right.Parameters[0]);//(body2.Arguments[0]);

            IDbQueryable sQuery = (IDbQueryable)((exp.Expressions[0] as ConstantExpression).Value);

            if (sQuery.DbExpressions.Count == 1 && sQuery.DbExpressions[0].DbExpressionType == DbExpressionType.GetTable)
            {
                if (!_appendedKeyword)
                {
                    jf.AppendNewLine();
                    jf.Append(_keywordName);
                    _appendedKeyword = true;
                }
                else
                {
                    jf.Append(',');
                    jf.AppendNewLine();
                    jf.Append("     ");
                }

                jf.Append(' ');
                Type type        = exp.Expressions[0].Type.GetGenericArguments()[0];
                var  typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(type);
                jf.AppendMember(typeRuntime.TableName, !typeRuntime.IsTemporary);

                jf.Append(' ');
                jf.Append(alias);
                if (on.Length > 0)
                {
                    on.Append(" AND ");
                }
            }
            else
            {
                useExists = true;
                if ((wf != null && wf.Length > 0) || (on != null && on.Length > 0))
                {
                    if (wf != null && wf.Length > 0)
                    {
                        wf.Append("AND ");
                    }
                    wf.AppendNewLine();
                }

                wf.Append("EXISTS(");
                wf.Indent += 1;
                wf.AppendNewLine();
                wf.Append("SELECT 1 FROM(");
                var cmd = sQuery.Resolve(wf.Indent + 1, false, wf.Parameters);
                wf.Append(cmd.CommandText);
                wf.AppendNewLine();
                wf.Append(')');
                wf.Append(' ');
                wf.Append(alias);
                wf.Append(" WHERE ");
            }

            ISqlBuilder tbuilder = useExists ? wf : on;

            if (body1 == null)
            {
                tbuilder.AppendMember(aliases, left.Body.ReduceUnary());
                tbuilder.Append(" = ");
                tbuilder.AppendMember(aliases, right.Body.ReduceUnary());
            }
            else
            {
                for (int index = 0; index < body1.Arguments.Count; ++index)
                {
                    tbuilder.AppendMember(aliases, body1.Arguments[index]);
                    tbuilder.Append(" = ");
                    tbuilder.AppendMember(aliases, body2.Arguments[index]);
                    if (index < body1.Arguments.Count - 1)
                    {
                        tbuilder.Append(" AND ");
                    }
                }
            }

            if (useExists)
            {
                wf.Indent -= 1;
                wf.AppendNewLine();
                wf.Append(')');
            }
        }