C#使用SqlBulkCopy将DataTable写入数据库的表中（表不存在则创建新表,数据存在则更新,不存在则插入）

原文:.net使用SqlBulkCopy导入数据（创建新表）

.net2.0后ado.net提供了一个快速导入sqlserver的方法sqlbulkcopy.导入效率非常高. 

包装了一个简单的sqlbulkcopy类，用于数据从datatable导入到sqlserver.代码如下： 
 

    /// <summary>

        /// 将DataTable写入数据库的表中

        /// </summary>

        /// <param name="source">数据源DataTable</param>

        /// <param name="tableName">数据目标的表名</param>

        /// <param name="useTransaction">操作过程是否使用事务</param>

        /// <param name="databaseConnString">数据库连接字符串</param>

        /// <param name="dropTable">删除DB中已存在的表(并自动新建表)</param>

        /// <param name="primaryKeys">主键的列名</param>

        public void WriteToDataBase(DataTable source, string tableName, bool useTransaction, string databaseConnString, bool dropTable, string[] primaryKeys)

        {

            //判断表是否存在 

            SqlHelper.ConnectionString = databaseConnString;

            //dataHelper.IsConnString = true; //使用数据库连接字符串创建sqlserver操作对象 

            string sql = "select * from sys.objects where type='U' and name='" + tableName + "'";

            DataTable dt = SqlHelper.ExecuteDataset(sql).Tables[0];

            if (dt.Rows.Count > 0)

            {

                if (dropTable == true)

                {

                    sql = "drop table " + tableName + "";   //清除已存在的表

                    SqlHelper.ExecuteNonQuery(SqlHelper.ConnectionString, CommandType.Text, sql);

                }

                else

                {

                    SqlBulkCopy sqlbulkcopy = new SqlBulkCopy(databaseConnString, SqlBulkCopyOptions.UseInternalTransaction | SqlBulkCopyOptions.FireTriggers);

                    sqlbulkcopy.DestinationTableName = tableName;//数据库中的表名



                    sqlbulkcopy.WriteToServer(source);

                    return;

                }

            }

            this.CreateTable(source.Columns, tableName, primaryKeys);

            var sqlBulkCopy = new System.Data.SqlClient.SqlBulkCopy(databaseConnString, SqlBulkCopyOptions.FireTriggers);//启动触发器

            if (useTransaction == true)

            {

                sqlBulkCopy = new System.Data.SqlClient.SqlBulkCopy(databaseConnString, SqlBulkCopyOptions.UseInternalTransaction | SqlBulkCopyOptions.FireTriggers); //导入的数据在一个事务中 

            }

            sqlBulkCopy.DestinationTableName = tableName;

            foreach (DataColumn c in source.Columns)

            {

                sqlBulkCopy.ColumnMappings.Add(c.ColumnName, c.ColumnName);

            }

            //SqlBulkCopy.BulkCopyTimeout = this.timeout;  //超时时间 

            sqlBulkCopy.BatchSize = 3000;  //每次传输3000行 

            sqlBulkCopy.WriteToServer(source);

        }

 

        /// <summary>

        /// 创建表以及触发器

        /// </summary>

        /// <param name="columns">列名</param>

        /// <param name="tableName">表名</param>

        /// <param name="primaryKeys">主键的列名</param>

        public void CreateTable(System.Data.DataColumnCollection columns, string tableName, string[] primaryKeys)

        {

            if (primaryKeys == null || primaryKeys.Length < 1)

            {

                MessageBox.Show("主键不允许为空!");

                return;

            }

            StringBuilder sb = new StringBuilder();

            // sb.Append("create table [" + tableName + "] (autoId  int identity(1,1),");

            sb.Append("create table [" + tableName + "] (");

            foreach (DataColumn column in columns)

            {

                sb.Append(" [" + column.ColumnName + "] " + this.GetTableColumnType(column.DataType) + ",");

            }



            string sql = sb.ToString();

            sql = sql.TrimEnd(',');

            sql += ")";



            sb.Clear();

            var temp1 = primaryKeys;

            for (int i = 0; i < primaryKeys.Length; i++)

            {

                temp1[i] = tableName + "." + primaryKeys[i] + "=Inserted." + primaryKeys[i];

            }

            List<string> temp2 = new List<string>();

            for (int i = 0; i < columns.Count; i++)

            {

                temp2.Add(columns[i].ColumnName + "=Inserted." + columns[i].ColumnName);

            }

            List<string> temp3 = new List<string>();

            for (int i = 0; i < columns.Count; i++)

            {

                temp3.Add(columns[i].ColumnName);

            }

            sb.Append("CREATE TRIGGER [tri_" + tableName + "_edit]  ON [" + tableName + "] instead of insert as");

            sb.Append("  IF EXISTS (");

            sb.Append("SELECT * FROM    " + tableName + ",Inserted WHERE " + String.Join(" AND ", temp1) + ")");

            sb.Append(" UPDATE [" + tableName + "] SET " + string.Join(",", temp2) + " FROM [" + tableName + "] JOIN inserted ON " + String.Join(" AND ", temp1) + " ");

            sb.Append(" ELSE ");



            sb.Append(" INSERT  [" + tableName + "](" + string.Join(",", temp3) + ") SELECT  " + string.Join(",", temp3) + " FROM inserted  ");

           // sql = sql + " ; " + sb.ToString(); 

            SqlHelper.ExecuteNonQuery(SqlHelper.ConnectionString, CommandType.Text, sql);

            SqlHelper.ExecuteNonQuery(SqlHelper.ConnectionString, CommandType.Text, sb.ToString());

        }

 

       private string GetTableColumnType(System.Type type)

        {

            string result = "varchar(255)";

            string sDbType = type.ToString();

            switch (sDbType)

            {

                case "System.String":

                    break;

                case "System.Int16":

                    result = "int";

                    break;

                case "System.Int32":

                    result = "int";

                    break;

                case "System.Int64":

                    result = "float";

                    break;

                case "System.Decimal":

                    result = "decimal(18,4)";

                    break;

                case "System.Double":

                    result = "decimal(18,4)";

                    break;

                case "System.DateTime":

                    result = "datetime";

                    break;

                default:

                    break;

            }

            return result;

        }