PCB MS SQL 标量函数(CLR) 实现DataTable转Json方法

一.准备需转为json字符串的DataTable数据

在数据库中执行一段SQL返回的数据

需转换后的JSON字符串的效果

[{"TechName":"开料","ItemName":"综合利用率是否为最高","ItemPara":"/"},{"TechName":"开料","ItemName":"综合利用率","ItemPara":"68.36"},{"TechName":"开料","ItemName":"纬向余料","ItemPara":"0"},{"TechName":"开料","ItemName":"经向余料","ItemPara":"0"},{"TechName":"开料","ItemName":"是否为小交货面积拼板","ItemPara":"n"},{"TechName":"开料","ItemName":"纬向尺寸","ItemPara":"24"},{"TechName":"开料","ItemName":"是否为阴阳铜结构","ItemPara":"N"},{"TechName":"开料","ItemName":"是否横竖开料","ItemPara":"N"},{"TechName":"开料","ItemName":"生产尺寸长","ItemPara":"24"},{"TechName":"开料","ItemName":"生产尺寸宽","ItemPara":"18"},{"TechName":"开料","ItemName":"拼板利用率","ItemPara":"68.36"},{"TechName":"开料","ItemName":"开料图纸","ItemPara":"/"},{"TechName":"开料","ItemName":"是否顾客指定板材","ItemPara":"N"},{"TechName":"开料","ItemName":"开料数","ItemPara":"4"},{"TechName":"开料","ItemName":"大料经向尺寸","ItemPara":"36"},{"TechName":"开料","ItemName":"大料纬向尺寸","ItemPara":"48"},{"TechName":"开料","ItemName":"成品尺寸长","ItemPara":"12"},{"TechName":"开料","ItemName":"成品尺寸宽","ItemPara":"13.5"},{"TechName":"开料","ItemName":"是否为PTFE板材","ItemPara":"N"},{"TechName":"开料","ItemName":"交货拼板个数","ItemPara":"1"},{"TechName":"开料","ItemName":"生产拼板个数","ItemPara":"1176"},{"TechName":"开料","ItemName":"交货单位","ItemPara":"U"},{"TechName":"开料","ItemName":"是否为凹蚀板材","ItemPara":"N"}]

二.C#写SQL SERVER(CLR)转JSON函数

先执行SQL返回DataTable,接着再将DataTable转为Json, 这里转为Json有2种方法,代码都贴在下方了

        /// <summary>
        /// 执行SQL语句 返回的DataTable 转为 Json
        /// </summary>
        /// <param name="StrSQL"></param>
        /// <returns></returns>
        [Microsoft.SqlServer.Server.SqlFunction(DataAccess = DataAccessKind.Read)]
        public static string ExecSQL2Json(string StrSQL)
        {
            DataTable dt = getDataTable(StrSQL);
            //return DataTable2Json(dt);  //方法1    转为 Json
            if (dt is null)
                return null;
            List<Dictionary<string, object>> list = new List<Dictionary<string, object>>();
            foreach (DataRow dr in dt.Rows)
            {
                Dictionary<string, object> result = new Dictionary<string, object>();
                foreach (DataColumn dc in dt.Columns)
                {
                    result.Add(dc.ColumnName, dr[dc].ToString());
                }
                list.Add(result);
            }
            return Json.Serialize(list);//方法2    转为 Json
        }
        /// <summary>
        /// 执行SQL获取DataTable
        /// </summary>
        /// <param name="StrSQL"></param>
        /// <returns></returns>
        private static DataTable getDataTable(string StrSQL)
        {
            DataTable dt = new DataTable();
            try
            {
                using (SqlConnection cn = new SqlConnection("context connection=true"))
                {
                    using (SqlDataAdapter da = new SqlDataAdapter(StrSQL, cn))
                    {
                        DataSet ds = new DataSet();
                        da.Fill(ds, "tab");
                        dt = ds.Tables["tab"];
                    }
                }
            }
            catch (Exception ex)
            {
                throw;
            }
            return dt;
        }

方法一：DataTable转Json

        /// <summary>
        /// DataTable转Json
        /// </summary>
        /// <param name="table"></param>
        /// <returns></returns>
        public static string DataTable2Json(DataTable table)
        {
            var JsonString = new StringBuilder();
            if (table.Rows.Count > )
            {
                JsonString.Append("[");
                for (int i = ; i < table.Rows.Count; i++)
                {
                    JsonString.Append("{");
                    for (int j = ; j < table.Columns.Count; j++)
                    {
                        object ValueNull = table.Rows[i][j];
                        if (ValueNull == DBNull.Value)
                        {
                            JsonString.Append("\"" + table.Columns[j].ColumnName.ToString() + "\":null" + ((j < table.Columns.Count - ) ? "," : ""));
                        }
                        else
                        {
                            string Value = table.Rows[i][j].ToString();
                            if (table.Columns[j].DataType == typeof(string) || table.Columns[j].DataType == typeof(DateTime) || table.Columns[j].DataType == typeof(Guid))
                            {
                                JsonString.Append("\"" + table.Columns[j].ColumnName.ToString() + "\":" + "\"" + Value + "\"" + ((j < table.Columns.Count - ) ? "," : ""));
                            }
                            else
                            {
                                if (table.Columns[j].DataType == typeof(bool)) Value = Value.ToLower();
                                JsonString.Append("\"" + table.Columns[j].ColumnName.ToString() + "\":" + Value + ((j < table.Columns.Count - ) ? "," : ""));
                            }
                        }

                    }
                    JsonString.Append("}" + ((i < table.Rows.Count - ) ? "," : ""));
                }
                JsonString.Append("]");
            }
            return JsonString.ToString();
        }

方法二:  开源MiniJSON类解析Json字符串

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace SQLClr
{
    /// <summary>
    /// This class encodes and decodes JSON strings.
    /// Spec. details, see http://www.json.org/
    ///
    /// JSON uses Arrays and Objects. These correspond here to the datatypes IList and IDictionary.
    /// All numbers are parsed to doubles.
    /// </summary>
    public static class Json
    {
        /// <summary>
        /// Parses the string json into a value
        /// </summary>
        /// <param name="json">A JSON string.</param>
        /// <returns>An List<object>, a Dictionary<string, object>, a double, an integer,a string, null, true, or false</returns>
        //反序列化
        public static object Deserialize(string json)
        {
            // save the string for debug information
            if (json == null)
            {
                return null;
            }

            return Parser.Parse(json);
        }
        //阻止其他类从该类继承
        sealed class Parser : IDisposable
        {
            const string WORD_BREAK = "{}[],:\"";

            public static bool IsWordBreak(char c)
            {
                //     如果 c 是空白，则为 true；否则，为 false;报告指定 Unicode 字符在此字符串中的第一个匹配项的索引。
                return Char.IsWhiteSpace(c) || WORD_BREAK.IndexOf(c) != -;
            }

            enum TOKEN
            {
                NONE,
                CURLY_OPEN,
                CURLY_CLOSE,
                SQUARED_OPEN,
                SQUARED_CLOSE,
                COLON,
                COMMA,
                STRING,
                NUMBER,
                TRUE,
                FALSE,
                NULL
            };
            //     实现从字符串进行读取的 System.IO.TextReader。
            StringReader json;

            Parser(string jsonString)
            {
                json = new StringReader(jsonString);
            }

            public static object Parse(string jsonString)
            {
                using (var instance = new Parser(jsonString))
                {
                    return instance.ParseValue();
                }
            }
            //释放
            public void Dispose()
            {
                json.Dispose();
                json = null;
            }

            Dictionary<string, object> ParseObject()
            {
                Dictionary<string, object> table = new Dictionary<string, object>();

                // ditch opening brace
                json.Read();

                // {
                while (true)
                {
                    switch (NextToken)
                    {
                        case TOKEN.NONE:
                            return null;
                        case TOKEN.COMMA:
                            continue;
                        case TOKEN.CURLY_CLOSE:
                            return table;
                        default:
                            // name
                            string name = ParseString();
                            if (name == null)
                            {
                                return null;
                            }

                            // :
                            if (NextToken != TOKEN.COLON)
                            {
                                return null;
                            }
                            // ditch the colon
                            json.Read();

                            // value
                            table[name] = ParseValue();
                            break;
                    }
                }
            }

            List<object> ParseArray()
            {
                List<object> array = new List<object>();

                // ditch opening bracket
                json.Read();

                // [
                bool parsing = true;
                while (parsing)
                {
                    TOKEN nextToken = NextToken;

                    switch (nextToken)
                    {
                        case TOKEN.NONE:
                            return null;
                        case TOKEN.COMMA:
                            continue;
                        case TOKEN.SQUARED_CLOSE:
                            parsing = false;
                            break;
                        default:
                            object value = ParseByToken(nextToken);

                            array.Add(value);
                            break;
                    }
                }

                return array;
            }

            object ParseValue()
            {
                TOKEN nextToken = NextToken;
                return ParseByToken(nextToken);
            }

            object ParseByToken(TOKEN token)
            {
                switch (token)
                {
                    case TOKEN.STRING:
                        return ParseString();
                    case TOKEN.NUMBER:
                        return ParseNumber();
                    case TOKEN.CURLY_OPEN:
                        return ParseObject();
                    case TOKEN.SQUARED_OPEN:
                        return ParseArray();
                    case TOKEN.TRUE:
                        return true;
                    case TOKEN.FALSE:
                        return false;
                    case TOKEN.NULL:
                        return null;
                    default:
                        return null;
                }
            }

            string ParseString()
            {
                StringBuilder s = new StringBuilder();
                char c;

                // ditch opening quote
                json.Read();

                bool parsing = true;
                while (parsing)
                {

                    if (json.Peek() == -)
                    {
                        parsing = false;
                        break;
                    }

                    c = NextChar;
                    switch (c)
                    {
                        case '"':
                            parsing = false;
                            break;
                        case '\\':
                            if (json.Peek() == -)
                            {
                                parsing = false;
                                break;
                            }

                            c = NextChar;
                            switch (c)
                            {
                                case '"':
                                case '\\':
                                case '/':
                                    s.Append(c);
                                    break;
                                case 'b':
                                    s.Append('\b');
                                    break;
                                case 'f':
                                    s.Append('\f');
                                    break;
                                case 'n':
                                    s.Append('\n');
                                    break;
                                case 'r':
                                    s.Append('\r');
                                    break;
                                case 't':
                                    s.Append('\t');
                                    break;
                                case 'u':
                                    var hex = new char[];

                                    for (int i = ; i < ; i++)
                                    {
                                        hex[i] = NextChar;
                                    }

                                    s.Append((char)Convert.ToInt32(new string(hex), ));
                                    break;
                            }
                            break;
                        default:
                            s.Append(c);
                            break;
                    }
                }

                return s.ToString();
            }

            object ParseNumber()
            {
                string number = NextWord;
                // 摘要:
                //     报告指定 Unicode 字符在此字符串中的第一个匹配项的索引。
                //
                // 参数:
                //   value:
                //     要查找的 Unicode 字符。
                //
                // 返回结果:
                //     如果找到该字符，则为 value 的从零开始的索引位置；如果未找到，则为 -1。
                if (number.IndexOf('.') == -)
                {
                    long parsedInt;
                    //     将数字的字符串表示形式转换为它的等效 64 位有符号整数。一个指示转换是否成功的返回值。
                    Int64.TryParse(number, out parsedInt);
                    return parsedInt;
                }

                double parsedDouble;
                Double.TryParse(number, out parsedDouble);
                return parsedDouble;
            }
            //
            void EatWhitespace()
            {
                //指示指定字符串中位于指定位置处的字符是否属于空白类别。
                while (Char.IsWhiteSpace(PeekChar))
                {
                    json.Read();
                    //摘要:
                    //     返回下一个可用的字符，但不使用它。
                    //
                    // 返回结果:
                    //     表示下一个要读取的字符的整数，或者，如果没有更多的可用字符或该流不支持查找，则为 -1。
                    if (json.Peek() == -)
                    {
                        break;
                    }
                }
            }

            char PeekChar
            {
                get
                {
                    //     读取输入字符串中的下一个字符并将该字符的位置提升一个字符。
                    //
                    // 返回结果:
                    //     基础字符串中的下一个字符，或者如果没有更多的可用字符，则为 -1。
                    return Convert.ToChar(json.Peek());
                }
            }

            char NextChar
            {
                get
                {
                    return Convert.ToChar(json.Read());
                }
            }

            string NextWord
            {
                get
                {
                    //     表示可变字符字符串。无法继承此类。
                    StringBuilder word = new StringBuilder();

                    while (!IsWordBreak(PeekChar))
                    {
                        // 摘要:
                        //     在此实例的结尾追加指定 Unicode 字符的字符串表示形式。
                        //
                        // 参数:
                        //   value:
                        //     要追加的 Unicode 字符。
                        //
                        // 返回结果:
                        //     完成追加操作后对此实例的引用。
                        word.Append(NextChar);
                        //下一个字符为空
                        if (json.Peek() == -)
                        {
                            break;
                        }
                    }
                    //
                    return word.ToString();
                }
            }

            TOKEN NextToken
            {
                get
                {
                    EatWhitespace();

                    if (json.Peek() == -)
                    {
                        return TOKEN.NONE;
                    }

                    switch (PeekChar)
                    {
                        case '{':
                            return TOKEN.CURLY_OPEN;
                        case '}':
                            json.Read();
                            return TOKEN.CURLY_CLOSE;
                        case '[':
                            return TOKEN.SQUARED_OPEN;
                        case ']':
                            json.Read();
                            return TOKEN.SQUARED_CLOSE;
                        case ',':
                            json.Read();
                            return TOKEN.COMMA;
                        case '"':
                            return TOKEN.STRING;
                        case ':':
                            return TOKEN.COLON;
                        case '':
                        case '':
                        case '':
                        case '':
                        case '':
                        case '':
                        case '':
                        case '':
                        case '':
                        case '':
                        case '-':
                            return TOKEN.NUMBER;
                    }

                    switch (NextWord)
                    {
                        case "false":
                            return TOKEN.FALSE;
                        case "true":
                            return TOKEN.TRUE;
                        case "null":
                            return TOKEN.NULL;
                    }

                    return TOKEN.NONE;
                }
            }
        }

        /// <summary>
        /// Converts a IDictionary / IList object or a simple type (string, int, etc.) into a JSON string
        /// </summary>
        /// <param name="json">A Dictionary<string, object> / List<object></param>
        /// <returns>A JSON encoded string, or null if object 'json' is not serializable</returns>
        public static string Serialize(object obj)
        {
            return Serializer.Serialize(obj);
        }

        sealed class Serializer
        {
            StringBuilder builder;

            Serializer()
            {
                //创建生成器
                builder = new StringBuilder();
            }
            //序列化
            public static string Serialize(object obj)
            {
                var instance = new Serializer();

                instance.SerializeValue(obj);

                return instance.builder.ToString();
            }
            //类型
            void SerializeValue(object value)
            {
                IList asList;
                IDictionary asDict;
                string asStr;

                if (value == null)
                {
                    builder.Append("null");
                }
                else if ((asStr = value as string) != null)
                {
                    SerializeString(asStr);
                }
                else if (value is bool)
                {
                    builder.Append((bool)value ? "true" : "false");
                }
                else if ((asList = value as IList) != null)
                {
                    SerializeArray(asList);
                }
                else if ((asDict = value as IDictionary) != null)
                {
                    SerializeObject(asDict);
                }
                else if (value is char)
                {
                    SerializeString(new string((char)value, ));
                }
                else
                {
                    SerializeOther(value);
                }
            }
            //序列化对象
            void SerializeObject(IDictionary obj)
            {
                bool first = true;

                builder.Append('{');

                foreach (object e in obj.Keys)
                {
                    if (!first)
                    {
                        builder.Append(',');
                    }

                    SerializeString(e.ToString());
                    builder.Append(':');

                    SerializeValue(obj[e]);

                    first = false;
                }

                builder.Append('}');
            }
            // 序列化数组
            void SerializeArray(IList anArray)
            {
                builder.Append('[');

                bool first = true;

                foreach (object obj in anArray)
                {
                    if (!first)
                    {
                        builder.Append(',');
                    }

                    SerializeValue(obj);

                    first = false;
                }

                builder.Append(']');
            }
            //string
            void SerializeString(string str)
            {
                builder.Append('\"');

                char[] charArray = str.ToCharArray();
                foreach (var c in charArray)
                {
                    switch (c)
                    {
                        case '"':
                            builder.Append("\\\"");
                            break;
                        case '\\':
                            builder.Append("\\\\");
                            break;
                        case '\b':
                            builder.Append("\\b");
                            break;
                        case '\f':
                            builder.Append("\\f");
                            break;
                        case '\n':
                            builder.Append("\\n");
                            break;
                        case '\r':
                            builder.Append("\\r");
                            break;
                        case '\t':
                            builder.Append("\\t");
                            break;
                        default:
                            int codepoint = Convert.ToInt32(c);
                            if ((codepoint >= ) && (codepoint <= ))
                            {
                                builder.Append(c);
                            }
                            else
                            {
                                //builder.Append("\\u");
                                //builder.Append(codepoint.ToString("x4"));
                                builder.Append(c);
                            }
                            break;
                    }
                }

                builder.Append('\"');
            }
            //其他
            void SerializeOther(object value)
            {
                // NOTE: decimals lose precision during serialization.
                // They always have, I'm just letting you know.
                // Previously floats and doubles lost precision too.
                //注意：小数在序列化过程中丢失精度。
                //他们总是有，我只是让你知道。
                //以前失去精度和双精度浮点数。
                if (value is float)
                {
                    builder.Append(((float)value).ToString("R"));
                }
                else if (value is int
                  || value is uint
                  || value is long
                  || value is sbyte
                  || value is byte
                  || value is short
                  || value is ushort
                  || value is ulong)
                {
                    builder.Append(value);
                }
                else if (value is double
                  || value is decimal)
                {
                    builder.Append(Convert.ToDouble(value).ToString("R"));
                }
                else
                {
                    SerializeString(value.ToString());
                }
            }
        }
    }
}

三.SQL服务器CLR配置（允许SQL调用.net程序）

    sp_configure 'show advanced options', 1;
    RECONFIGURE WITH override
    GO
    sp_configure 'clr enabled', 1;
    RECONFIGURE WITH override
    GO
    Sp_changedbowner 'sa',true   --sa改为当前登入用户名
    alter database [dbname] set trustworthy on    --bbname 改为自己的库名

四.注册 CLR 程序集

   create  ASSEMBLY SQLfunctionAssembly
   FROM 'D:\SQLClr.dll'      --改为自己C#写的dll路径填写
   WITH PERMISSION_SET = UNSAFE;   

创建的.net程序集数据会写入下表：

  select * from sys.assemblies
  select  * from sys.assembly_files

五.创建标量函数

create  FUNCTION [dbo].[ExecSQL2Json](@StrSQL [nvarchar](max))
RETURNS [nvarchar](max) WITH EXECUTE AS CALLER
AS
EXTERNAL NAME [SQLfunctionAssembly].[SQLClr.SQLfunction].[ExecSQL2Json]

六.测试DataTable转Json函数

DECLARE @SQL VARCHAR(MAX)
SET @SQL = 'SELECT TechName,ItemName,ItemPara
            FROM FP_EMS_DB.dbo.V_ppegeneral
            WHERE pdctno = ''2V011Z30A4'' AND TechNo = ''CC_01'' ORDER BY ItemNo '
SELECT  dbo.ExecSQL2Json(@SQL)

运行后结果

七.小结

采用CLR方式写SQL SERVER函数转为json字符串，那么只要传入一段SQL语句就可以转为Json字符串，是不是很方便，但这种作法在实际应用中作用不太大,因为业务系统现在基本采用ORM 对象关系映射模型开发,数据库表映射成对象，直接操作的对象，然而对象转为json放在应用程序端转换是及为方便的，在这里只开拓一种新思路在数据库中实现转json的方法。