DbHelperSQL

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
namespace System {
    [System.Diagnostics.DebuggerDisplay("connectionString={connectionString}")]
    public abstract class DbHelperSQL {
        public static string connectionString = AppConfig.connString.ToString();
        public DbHelperSQL() {
        }
        #region 公用方法
        public static bool ColumnExists(string tableName,string columnName) {
            string sql = "select count(1) from syscolumns where [id]=object_id('" + tableName + "') and [name]='" + columnName + "'";
            object res = GetSingle(sql);
            if(res == null) {
                return false;
            }
            return Convert.ToInt32(res) > 0;
        }
        public static int GetMaxID(string FieldName,string TableName) {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = GetSingle(strsql);
            if(obj == null) {
                return 1;
            } else {
                return int.Parse(obj.ToString());
            }
        }
        public static bool Exists(string strSql) {
            object obj = GetSingle(strSql);
            int cmdresult;
            if((Object.Equals(obj,null)) || (Object.Equals(obj,System.DBNull.Value))) {
                cmdresult = 0;
            } else {
                cmdresult = int.Parse(obj.ToString());
            }
            if(cmdresult == 0) {
                return false;
            } else {
                return true;
            }
        }
        public static bool IsSysObjects(string TableName) {
            string strsql = "select count(*) from sysobjects where id = object_id(N'[" + TableName + "]') ";
            object obj = GetSingle(strsql);
            int cmdresult;
            if((Object.Equals(obj,null)) || (Object.Equals(obj,System.DBNull.Value))) {
                cmdresult = 0;
            } else {
                cmdresult = int.Parse(obj.ToString());
            }
            if(cmdresult == 0) {
                return false;
            } else {
                return true;
            }
        }
        public static bool Exists(string strSql,params SqlParameter[] cmdParms) {
            object obj = GetSingle(strSql,cmdParms);
            int cmdresult;
            if((Object.Equals(obj,null)) || (Object.Equals(obj,System.DBNull.Value))) {
                cmdresult = 0;
            } else {
                cmdresult = int.Parse(obj.ToString());
            }
            if(cmdresult == 0) {
                return false;
            } else {
                return true;
            }
        }
        #endregion
        #region  执行简单SQL语句
        public static int ExecuteSql(string SQLString) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                using(SqlCommand cmd = new SqlCommand(SQLString,connection)) {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
            }
        }
        public static int ExecuteSqlByTime(string SQLString,int Times) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                using(SqlCommand cmd = new SqlCommand(SQLString,connection)) {
                    connection.Open();
                    cmd.CommandTimeout = Times;
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
            }
        }
        public static int ExecuteSqlTran(List<String> SQLStringList) {
            using(SqlConnection conn = new SqlConnection(connectionString)) {
                conn.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = conn;
                SqlTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try {
                    int count = 0;
                    for(int n = 0;n < SQLStringList.Count;n++) {
                        string strsql = SQLStringList[n];
                        if(strsql.Trim().Length > 1) {
                            cmd.CommandText = strsql;
                            count += cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                    return count;
                } catch {
                    tx.Rollback();
                    return 0;
                }
            }
        }
        public static void Addbatches(List<String> SQLStringList) {
            //分批执行
            while(SQLStringList.Count > 0) {
                var tempParam = SQLStringList.Take(50).ToList();
                ExecuteSqlTran(tempParam);
                SQLStringList.RemoveRange(0,tempParam.Count);
            }
        }
        public static void ExecuteSql(SQLParma parma) {
            ExecuteSql(parma.Sql,parma.Sp);
        }
        public static int ExecuteSql(string SQLString,string content) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                SqlCommand cmd = new SqlCommand(SQLString,connection);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@content",SqlDbType.NText);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                } finally {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        public static object ExecuteSqlGet(string SQLString,string content) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                SqlCommand cmd = new SqlCommand(SQLString,connection);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@content",SqlDbType.NText);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try {
                    connection.Open();
                    object obj = cmd.ExecuteScalar();
                    if((Object.Equals(obj,null)) || (Object.Equals(obj,System.DBNull.Value))) {
                        return null;
                    } else {
                        return obj;
                    }
                } finally {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        public static int ExecuteSqlInsertImg(string SQLString,byte[] fs) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                SqlCommand cmd = new SqlCommand(SQLString,connection);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@fs",SqlDbType.Image);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                } finally {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        public static object GetSingle(string SQLString) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                using(SqlCommand cmd = new SqlCommand(SQLString,connection)) {
                    connection.Open();
                    object obj = cmd.ExecuteScalar();
                    if((Object.Equals(obj,null)) || (Object.Equals(obj,System.DBNull.Value))) {
                        return null;
                    } else {
                        return obj;
                    }
                }
            }
        }
        public static object GetSingle(string SQLString,int Times) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                using(SqlCommand cmd = new SqlCommand(SQLString,connection)) {
                    connection.Open();
                    cmd.CommandTimeout = Times;
                    object obj = cmd.ExecuteScalar();
                    if((Object.Equals(obj,null)) || (Object.Equals(obj,System.DBNull.Value))) {
                        return null;
                    } else {
                        return obj;
                    }
                }
            }
        }
        public static SqlDataReader ExecuteReader(string SQLString) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                using(SqlCommand cmd = new SqlCommand(SQLString,connection)) {
                    connection.Open();
                    SqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                    return myReader;
                }
            }
        }
        public static DataSet Query(string SQLString) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                DataSet ds = new DataSet();
                connection.Open();
                SqlDataAdapter command = new SqlDataAdapter(SQLString,connection);
                command.Fill(ds,"ds");
                return ds;
            }
        }
        public static DataSet Query(string SQLString,int Times) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                DataSet ds = new DataSet();
                connection.Open();
                SqlDataAdapter command = new SqlDataAdapter(SQLString,connection);
                command.SelectCommand.CommandTimeout = Times;
                command.Fill(ds,"ds");
                return ds;
            }
        }
        public static DataTable ExecuteTable(string SQLString) {
            var ds = Query(SQLString);
            if(ds != null && ds.Tables.Count > 0) {
                return ds.Tables[0];
            } else {
                return null;
            }
        }
        public static DataRow ExecuteRow(string SQLString) {
            var ds = Query(SQLString);
            if(ds != null && ds.Tables.Count > 0) {
                if(ds.Tables[0].Rows.Count > 0) {
                    return ds.Tables[0].Rows[0];
                } else {
                    return null;
                }
            } else {
                return null;
            }
        }
        #endregion
        #region 执行带参数的SQL语句
        public static int ExecuteSql(string SQLString,params SqlParameter[] cmdParms) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                using(SqlCommand cmd = new SqlCommand()) {
                    PrepareCommand(cmd,connection,null,SQLString,cmdParms);
                    int rows = cmd.ExecuteNonQuery();
                    cmd.Parameters.Clear();
                    return rows;
                }
            }
        }
        public static void ExecuteSqlTran(Hashtable SQLStringList) {
            using(SqlConnection conn = new SqlConnection(connectionString)) {
                conn.Open();
                using(SqlTransaction trans = conn.BeginTransaction()) {
                    SqlCommand cmd = new SqlCommand();
                    try {
                        foreach(DictionaryEntry myDE in SQLStringList) {
                            string cmdText = myDE.Key.ToString();
                            SqlParameter[] cmdParms = (SqlParameter[])myDE.Value;
                            PrepareCommand(cmd,conn,trans,cmdText,cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    } catch(System.Data.SqlClient.SqlException ex) {
                        Logger.LogError("DbHelperSQL ExecuteSqlTran connectionString=" + connectionString,ex);
                        trans.Rollback();
                    }
                }
            }
        }
        public static void ExecuteSqlTranWithIndentity(Hashtable SQLStringList) {
            using(SqlConnection conn = new SqlConnection(connectionString)) {
                conn.Open();
                using(SqlTransaction trans = conn.BeginTransaction()) {
                    SqlCommand cmd = new SqlCommand();
                    try {
                        int indentity = 0;
                        foreach(DictionaryEntry myDE in SQLStringList) {
                            string cmdText = myDE.Key.ToString();
                            SqlParameter[] cmdParms = (SqlParameter[])myDE.Value;
                            foreach(SqlParameter q in cmdParms) {
                                if(q.Direction == ParameterDirection.InputOutput) {
                                    q.Value = indentity;
                                }
                            }
                            PrepareCommand(cmd,conn,trans,cmdText,cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            foreach(SqlParameter q in cmdParms) {
                                if(q.Direction == ParameterDirection.Output) {
                                    indentity = Convert.ToInt32(q.Value);
                                }
                            }
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    } catch {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }
        public static object GetSingle(string SQLString,params SqlParameter[] cmdParms) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                using(SqlCommand cmd = new SqlCommand()) {
                    PrepareCommand(cmd,connection,null,SQLString,cmdParms);
                    object obj = cmd.ExecuteScalar();
                    cmd.Parameters.Clear();
                    if((Object.Equals(obj,null)) || (Object.Equals(obj,System.DBNull.Value))) {
                        return null;
                    } else {
                        return obj;
                    }
                }
            }
        }
        public static SqlDataReader ExecuteReader(string SQLString,params SqlParameter[] cmdParms) {
            SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd,connection,null,SQLString,cmdParms);
            SqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            cmd.Parameters.Clear();
            return myReader;
        }
        public static DataSet Query(string SQLString,params SqlParameter[] cmdParms) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd,connection,null,SQLString,cmdParms);
                using(SqlDataAdapter da = new SqlDataAdapter(cmd)) {
                    DataSet ds = new DataSet();
                    da.Fill(ds,"ds");
                    cmd.Parameters.Clear();
                    return ds;
                }
            }
        }
        private static void PrepareCommand(SqlCommand cmd,SqlConnection conn,SqlTransaction trans,string cmdText,SqlParameter[] cmdParms) {
            if(conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if(trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;
            if(cmdParms != null) {
                foreach(SqlParameter parameter in cmdParms) {
                    if((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&
                        (parameter.Value == null)) {
                        parameter.Value = DBNull.Value;
                    }
                    cmd.Parameters.Add(parameter);
                }
            }
        }
        #endregion
        #region 存储过程操作
        public static SqlDataReader RunProcedure(string storedProcName,IDataParameter[] parameters) {
            SqlConnection connection = new SqlConnection(connectionString);
            SqlDataReader returnReader;
            connection.Open();
            SqlCommand command = BuildQueryCommand(connection,storedProcName,parameters);
            command.CommandType = CommandType.StoredProcedure;
            returnReader = command.ExecuteReader(CommandBehavior.CloseConnection);
            return returnReader;
        }
        public static DataSet RunProcedure(string storedProcName,IDataParameter[] parameters,string tableName) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                DataSet dataSet = new DataSet();
                connection.Open();
                SqlDataAdapter sqlDA = new SqlDataAdapter();
                sqlDA.SelectCommand = BuildQueryCommand(connection,storedProcName,parameters);
                sqlDA.Fill(dataSet,tableName);
                connection.Close();
                return dataSet;
            }
        }
        public static DataSet RunProcedure(string storedProcName,IDataParameter[] parameters,string tableName,int Times) {
            using(SqlConnection connection = new SqlConnection(connectionString)) {
                DataSet dataSet = new DataSet();
                connection.Open();
                SqlDataAdapter sqlDA = new SqlDataAdapter();
                sqlDA.SelectCommand = BuildQueryCommand(connection,storedProcName,parameters);
                sqlDA.SelectCommand.CommandTimeout = Times;
                sqlDA.Fill(dataSet,tableName);
                connection.Close();
                return dataSet;
            }
        }
        private static SqlCommand BuildQueryCommand(SqlConnection connection,string storedProcName,IDataParameter[] parameters) {
            SqlCommand command = new SqlCommand(storedProcName,connection);
            command.CommandType = CommandType.StoredProcedure;
            foreach(SqlParameter parameter in parameters) {
                if(parameter != null) {
                    if((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&
                        (parameter.Value == null)) {
                        parameter.Value = DBNull.Value;
                    }
                    command.Parameters.Add(parameter);
                }
            }
            return command;
        }
        #endregion
        #region  MethodEx
        public static bool OpenDb(string connectionString) {
            try {
                using(SqlConnection connection = new SqlConnection(connectionString)) {
                    using(SqlCommand cmd = new SqlCommand("select GETDATE()",connection)) {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if((Object.Equals(obj,null)) || (Object.Equals(obj,System.DBNull.Value))) {
                            return false;
                        } else {
                            return true;
                        }
                    }
                }
            } catch(Exception ex) {
                return false;
            }
        }
        public static void SqlBulkCopyInsert(DataTable dtData) {
            using(SqlBulkCopy sqlRevdBulkCopy = new SqlBulkCopy(connectionString)) {
                sqlRevdBulkCopy.DestinationTableName = string.IsNullOrWhiteSpace(dtData.TableName) ? "tempdatatable_admin_" + DateTime.Now.ToShortDateString() : dtData.TableName;
                sqlRevdBulkCopy.NotifyAfter = dtData.Rows.Count;
                sqlRevdBulkCopy.WriteToServer(dtData);
                sqlRevdBulkCopy.Close();
            }
        }
        public static string Exec(string sql) {
            string show = "";
            using(SqlConnection con = new SqlConnection(connectionString)) {
                try {
                    con.Open();
                    SqlCommand Com = new SqlCommand(sql,con);
                    show = Com.ExecuteScalar().ToString();
                } catch {
                    show = "";
                }
                return show.ToString();
            }
        }
        public static SqlParameter[] GetSqlParameter(List<SqlParam> sqlParams) {
            List<SqlParameter> L_pars = new List<SqlParameter>();
            foreach(var item in sqlParams) {
                L_pars.Add(new SqlParameter(item.ParamName,item.ParamValue));
            }
            return L_pars.ToArray();
        }
        public static DataTable ExecuteTable(string SQLString,params SqlParameter[] cmdParms) {
            var ds = Query(SQLString,cmdParms);
            if(ds != null && ds.Tables.Count > 0) {
                return ds.Tables[0];
            } else {
                return null;
            }
        }
        public static T GetSingle<T>(string commandText,params SqlParameter[] parms) {
            object result = GetSingle(commandText,parms);
            if(result != null) {
                return (T)Convert.ChangeType(result,typeof(T));
                ;
            }
            return default(T);
        }
        public static string GetFieldValue(string fieldName,string tableName,string strWhere) {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("SELECT " + fieldName + " FROM " + tableName + " ");
            if(!string.IsNullOrWhiteSpace(strWhere)) {
                strSql.Append(" WHERE " + strWhere);
            }
            return DbHelperSQL.GetSingle<string>(strSql.ToString());
        }
        public static DataTable Get_PagingTable(string where,string ls_tablesql,string column,string sort,int page,int pageCount,SqlParameter[] parms) {
            string sql = @"select top (" + pageCount + ") * from (" + ls_tablesql + where + " ) as aaa   where aaa.RowId between ((" + page + "-1)*" + pageCount + "+1) and (" + page + "*" + pageCount + ") " + "order by  " + column + " " + sort + "";
            return ExecuteTable(sql,parms);
        }
        public static DataTable GetListByPage(string strWhere,string orderby,int startIndex,int endIndex,string tableName,params SqlParameter[] cmdParms) {
            int i_inde, i_end;
            i_end = startIndex * endIndex;
            i_inde = (startIndex - 1) * endIndex + 1;
            StringBuilder strSql = new StringBuilder();
            strSql.Append("SELECT * FROM ( ");
            strSql.Append(" SELECT ROW_NUMBER() OVER (");
            if(!string.IsNullOrWhiteSpace(orderby)) {
                strSql.Append("order by T." + orderby);
            } else {
                strSql.Append("order by T.Id desc");
            }
            strSql.Append(")AS Row, T.*  from " + tableName + " T ");
            if(!string.IsNullOrWhiteSpace(strWhere)) {
                strSql.Append(" WHERE " + strWhere);
            }
            strSql.Append(" ) TT");
            strSql.AppendFormat(" WHERE TT.Row between {0} and {1}",i_inde,i_end);
            return ExecuteTable(strSql.ToString(),cmdParms);
        }
        #endregion
        #region DataTable转换到List
        public static IList<T> ExecuteList<T>(string SQLString) {
            var ds = Query(SQLString);
            if(ds != null && ds.Tables.Count > 0) {
                return ToList<T>(ds.Tables[0]);
            } else {
                return null;
            }
        }
        public static DataTable ToDataTable<T>(IEnumerable<T> collection) {
            var props = typeof(T).GetProperties();
            var dt = new DataTable();
            dt.Columns.AddRange(props.Select(p => new DataColumn(p.Name,p.PropertyType)).ToArray());
            if(collection.Count() > 0) {
                for(int i = 0;i < collection.Count();i++) {
                    ArrayList tempList = new ArrayList();
                    foreach(PropertyInfo pi in props) {
                        object obj = pi.GetValue(collection.ElementAt(i),null);
                        tempList.Add(obj);
                    }
                    object[] array = tempList.ToArray();
                    dt.LoadDataRow(array,true);
                }
            }
            return dt;
        }
        public static IList<T> ToList<T>(DataTable table) {
            if(table == null) {
                return null;
            }
            List<DataRow> rows = new List<DataRow>();
            foreach(DataRow row in table.Rows) {
                rows.Add(row);
            }
            return ToList<T>(rows);
        }
        public static IList<T> ToList<T>(IList<DataRow> rows) {
            IList<T> list = null;
            if(rows != null) {
                list = new List<T>();
                foreach(DataRow row in rows) {
                    T item = ToModel<T>(row);
                    list.Add(item);
                }
            }
            return list;
        }
        public static T ToModel<T>(DataRow row) {
            T obj = default(T);
            if(row != null) {
                obj = Activator.CreateInstance<T>();
                foreach(DataColumn column in row.Table.Columns) {
                    PropertyInfo prop = obj.GetType().GetProperty(column.ColumnName);
                    try {
                        if(!prop.CanWrite) {
                            continue;
                        }
                        object value = row[column.ColumnName];
                        if(value != DBNull.Value) {
                            prop.SetValue(obj,value,null);
                        }
                    } catch(Exception ex) {
                        Logger.LogError(column.ColumnName + "字段类型与实体类型不匹配 " + ex.Message);
                    }
                }
            }
            return obj;
        }
        #endregion
        #region DbBackuper
        public Result BackupDatabase(string databaseName,string filename,bool isErase) {
            var result = DealFile(filename,isErase);
            if(result.Success) {
                try {
                    string strCmd = "BACKUP DATABASE " + databaseName + " TO DISK = " + filename + "";
                    ExecuteSql(strCmd);
                } catch(Exception ex) {
                    return new Result(ex);
                }
                return new Result(true);
            }
            return result;
        }
        /// <summary>
        /// 处理文件
        /// </summary>
        /// <param name="filename">文件名</param>
        /// <param name="isErase">是否擦除</param>
        /// <returns></returns>
        private static Result DealFile(string filename,bool isErase) {
            try {
                if(File.Exists(filename)) {
                    if(!isErase) {
                        return new Result("文件已经存在!");
                    } else {
                        File.Delete(filename);
                    }
                }
                string directory = Path.GetDirectoryName(filename);
                string file = Path.GetFileName(filename);
                if(!Directory.Exists(directory)) {
                    Directory.CreateDirectory(directory);
                }
                return new Result(true);
            } catch(Exception ex) {
                return new Result(ex);
            }
        }
        #endregion
        #region DbScriptBuilder

        #endregion
        #region DbObject
        public void ExtendedProperty(bool addbyupdate,string describe,string tableName,string columnName = null) {
            string sql_propertyInfo = @"EXEC sys.{0} N'MS_Description',N'{1}',N'SCHEMA',N'dbo',N'TABLE',N'{2}',N'COLUMN',N'{3}'";//字段说明
            string sql_propertyInfo1 = @"EXEC sys.{0} N'MS_Description',N'{1}',N'SCHEMA',N'dbo',N'TABLE',N'{2}'";//表说明
            string sql = "";
            if(addbyupdate) {
                if(columnName == null || columnName.Length == 0) {
                    sql = string.Format(sql_propertyInfo1,"sp_updateextendedproperty",describe,tableName);
                } else {
                    sql = string.Format(sql_propertyInfo,"sp_updateextendedproperty",describe,tableName,columnName);
                }
            } else {
                if(columnName == null || columnName.Length == 0) {
                    sql = string.Format(sql_propertyInfo1,"sp_addextendedproperty",describe,tableName);
                } else {
                    sql = string.Format(sql_propertyInfo,"sp_addextendedproperty",describe,tableName,columnName);
                }
            }
            ExecuteSql(sql);
        }
        public List<TableColumn> GetColumnInfoList(string tableName) {
            if(string.IsNullOrWhiteSpace(tableName)) return null;
            return Utils.GetOrAddCache(tableName,() => {
                string sql = @"SELECT 
d.name  AS 表名, 
isnull(f.value, '') AS 表说明, 
a.colorder AS 字段序号, 
a.name AS 字段名,ISNULL(g.[value], '') AS 字段说明, 
CASE WHEN COLUMNPROPERTY(a.id, a.name, 'IsIdentity') = 1 THEN '√' ELSE '' END AS 标识, 
CASE WHEN EXISTS(SELECT 1  FROM dbo.sysindexes si INNER JOIN 
dbo.sysindexkeys sik ON si.id = sik.id AND si.indid = sik.indid INNER JOIN dbo.syscolumns sc 
ON sc.id = sik.id AND sc.colid = sik.colid INNER JOIN  dbo.sysobjects so 
ON so.name = si.name AND so.xtype = 'PK' WHERE sc.id = a.id AND sc.colid = a.colid) THEN '√' ELSE '' END AS 主键, 
b.name AS 类型, a.length AS 长度, COLUMNPROPERTY(a.id, a.name, 'PRECISION')AS 精度, 
ISNULL(COLUMNPROPERTY(a.id, a.name, 'Scale'), 0) AS 小数位数,CASE WHEN a.isnullable = 1 THEN '√' ELSE '' END AS 允许空, 
ISNULL(e.text, '') AS 默认值 FROM dbo.syscolumns a LEFT OUTER JOIN   
dbo.systypes b ON a.xtype = b.xusertype INNER JOIN dbo.sysobjects d ON a.id = d.id AND d.xtype = 'U' AND  
d.status >= 0 LEFT OUTER JOIN   dbo.syscomments e ON a.cdefault = e.id LEFT OUTER JOIN sys.extended_properties g 
ON a.id = g.major_id AND a.colid = g.minor_id AND  g.name = 'MS_Description' LEFT OUTER JOIN  
sys.extended_properties f ON d.id = f.major_id AND f.minor_id = 0 AND f.name = 'MS_Description'  ";
                if(!string.IsNullOrWhiteSpace(tableName)) {
                    sql = sql + " where d.name='" + tableName + "'";
                }
                var list = new List<TableColumn>();
                var dt = ExecuteTable(string.Format(sql));
                foreach(DataRow row in dt.Rows) {
                    var tc = new TableColumn();
                    tc.TableName = row["表名"].ToString();
                    tc.ColumnName = row["字段名"].ToString();
                    tc.ColumnRemark = row["字段说明"].ToString();
                    tc.ColumnType = row["类型"].ToString();
                    tc.DefaultValue = row["默认值"].ToString();
                    tc.MaxLength = Utils.GetObjTranNull<int>(row["长度"].ToString());
                    tc.ColumnOrder = Utils.GetObjTranNull<int>(row["字段序号"]);
                    if(row["标识"].ToString().Length > 0) {
                        tc.IsIdentity = true;
                    }
                    if(row["主键"].ToString() == "√") {
                        tc.IsPrimaryKey = true;
                    }
                    if(row["允许空"].ToString() == "√") {
                        tc.IsNullable = true;
                    }
                    list.Add(tc);
                }
                return list;
            });
        }
        #endregion
    }
}