/// <summary>
  /// 提供數(shù)據(jù)批量處理的方法。
  /// </summary>
  public interface IBatcherProvider : IProviderService
  {
    /// <summary>
    /// 將 <see cref="DataTable"/> 的數(shù)據(jù)批量插入到數(shù)據(jù)庫中。
    /// </summary>
    /// <param name="dataTable">要批量插入的 <see cref="DataTable"/>。</param>
    /// <param name="batchSize">每批次寫入的數(shù)據(jù)量。</param>
    void Insert(DataTable dataTable, int batchSize = 10000);
  }

一、SqlServer數(shù)據(jù)批量插入

SqlServer的批量插入很簡單，使用SqlBulkCopy就可以，以下是該類的實現(xiàn)：

/// <summary>
  /// 為 System.Data.SqlClient 提供的用于批量操作的方法。
  /// </summary>
  public sealed class MsSqlBatcher : IBatcherProvider
  {
    /// <summary>
    /// 獲取或設(shè)置提供者服務(wù)的上下文。
    /// </summary>
    public ServiceContext ServiceContext { get; set; }

    /// <summary>
    /// 將 <see cref="DataTable"/> 的數(shù)據(jù)批量插入到數(shù)據(jù)庫中。
    /// </summary>
    /// <param name="dataTable">要批量插入的 <see cref="DataTable"/>。</param>
    /// <param name="batchSize">每批次寫入的數(shù)據(jù)量。</param>
    public void Insert(DataTable dataTable, int batchSize = 10000)
    {
      Checker.ArgumentNull(dataTable, "dataTable");
      if (dataTable.Rows.Count == 0)
      {
        return;
      }
      using (var connection = (SqlConnection)ServiceContext.Database.CreateConnection())
      {
        try
        {
          connection.TryOpen();
          //給表名加上前后導(dǎo)符
          var tableName = DbUtility.FormatByQuote(ServiceContext.Database.Provider.GetService<ISyntaxProvider>(), dataTable.TableName);
          using (var bulk = new SqlBulkCopy(connection, SqlBulkCopyOptions.KeepIdentity, null)
            {
              DestinationTableName = tableName, 
              BatchSize = batchSize
            })
          {
            //循環(huán)所有列，為bulk添加映射
            dataTable.EachColumn(c => bulk.ColumnMappings.Add(c.ColumnName, c.ColumnName), c => !c.AutoIncrement);
            bulk.WriteToServer(dataTable);
            bulk.Close();
          }
        }
        catch (Exception exp)
        {
          throw new BatcherException(exp);
        }
        finally
        {
          connection.TryClose();
        }
      }
    }
  }

以上沒有使用事務(wù)，使用事務(wù)在性能上會有一定的影響，如果要使用事務(wù)，可以設(shè)置SqlBulkCopyOptions.UseInternalTransaction。

二、Oracle數(shù)據(jù)批量插入

System.Data.OracleClient不支持批量插入，因此只能使用Oracle.DataAccess組件來作為提供者。

/// <summary>
  /// Oracle.Data.Access 組件提供的用于批量操作的方法。
  /// </summary>
  public sealed class OracleAccessBatcher : IBatcherProvider
  {
    /// <summary>
    /// 獲取或設(shè)置提供者服務(wù)的上下文。
    /// </summary>
    public ServiceContext ServiceContext { get; set; }

    /// <summary>
    /// 將 <see cref="DataTable"/> 的數(shù)據(jù)批量插入到數(shù)據(jù)庫中。
    /// </summary>
    /// <param name="dataTable">要批量插入的 <see cref="DataTable"/>。</param>
    /// <param name="batchSize">每批次寫入的數(shù)據(jù)量。</param>
    public void Insert(DataTable dataTable, int batchSize = 10000)
    {
      Checker.ArgumentNull(dataTable, "dataTable");
      if (dataTable.Rows.Count == 0)
      {
        return;
      }
      using (var connection = ServiceContext.Database.CreateConnection())
      {
        try
        {
          connection.TryOpen();
          using (var command = ServiceContext.Database.Provider.DbProviderFactory.CreateCommand())
          {
            if (command == null)
            {
              throw new BatcherException(new ArgumentException("command"));
            }
            command.Connection = connection;
            command.CommandText = GenerateInserSql(ServiceContext.Database, command, dataTable);
            command.ExecuteNonQuery();
          }
        }
        catch (Exception exp)
        {
          throw new BatcherException(exp);
        }
        finally
        {
          connection.TryClose();
        }
      }
    }

    /// <summary>
    /// 生成插入數(shù)據(jù)的sql語句。
    /// </summary>
    /// <param name="database"></param>
    /// <param name="command"></param>
    /// <param name="table"></param>
    /// <returns></returns>
    private string GenerateInserSql(IDatabase database, DbCommand command, DataTable table)
    {
      var names = new StringBuilder();
      var values = new StringBuilder();
      //將一個DataTable的數(shù)據(jù)轉(zhuǎn)換為數(shù)組的數(shù)組
      var data = table.ToArray();

      //設(shè)置ArrayBindCount屬性
      command.GetType().GetProperty("ArrayBindCount").SetValue(command, table.Rows.Count, null);

      var syntax = database.Provider.GetService<ISyntaxProvider>();
      for (var i = 0; i < table.Columns.Count; i++)
      {
        var column = table.Columns[i];

        var parameter = database.Provider.DbProviderFactory.CreateParameter();
        if (parameter == null)
        {
          continue;
        }
        parameter.ParameterName = column.ColumnName;
        parameter.Direction = ParameterDirection.Input;
        parameter.DbType = column.DataType.GetDbType();
        parameter.Value = data[i];

        if (names.Length > 0)
        {
          names.Append(",");
          values.Append(",");
        }
        names.AppendFormat("{0}", DbUtility.FormatByQuote(syntax, column.ColumnName));
        values.AppendFormat("{0}{1}", syntax.ParameterPrefix, column.ColumnName);

        command.Parameters.Add(parameter);
      }
      return string.Format("INSERT INTO {0}({1}) VALUES ({2})", DbUtility.FormatByQuote(syntax, table.TableName), names, values);
    }
  }

以上最重要的一步，就是將DataTable轉(zhuǎn)為數(shù)組的數(shù)組表示，即object[][]，前數(shù)組的上標(biāo)是列的個數(shù)，后數(shù)組是行的個數(shù)，因此循環(huán)Columns將后數(shù)組作為Parameter的值，也就是說，參數(shù)的值是一個數(shù)組。而insert語句與一般的插入語句沒有什么不一樣。

三、SQLite數(shù)據(jù)批量插入

SQLite的批量插入只需開啟事務(wù)就可以了，這個具體的原理不得而知。

public sealed class SQLiteBatcher : IBatcherProvider
  {
    /// <summary>
    /// 獲取或設(shè)置提供者服務(wù)的上下文。
    /// </summary>
    public ServiceContext ServiceContext { get; set; }

    /// <summary>
    /// 將 <see cref="DataTable"/> 的數(shù)據(jù)批量插入到數(shù)據(jù)庫中。
    /// </summary>
    /// <param name="dataTable">要批量插入的 <see cref="DataTable"/>。</param>
    /// <param name="batchSize">每批次寫入的數(shù)據(jù)量。</param>
    public void Insert(DataTable dataTable, int batchSize = 10000)
    {
      Checker.ArgumentNull(dataTable, "dataTable");
      if (dataTable.Rows.Count == 0)
      {
        return;
      }
      using (var connection = ServiceContext.Database.CreateConnection())
      {
        DbTransaction transcation = null;
        try
        {
          connection.TryOpen();
          transcation = connection.BeginTransaction();
          using (var command = ServiceContext.Database.Provider.DbProviderFactory.CreateCommand())
          {
            if (command == null)
            {
              throw new BatcherException(new ArgumentException("command"));
            }
            command.Connection = connection;

            command.CommandText = GenerateInserSql(ServiceContext.Database, dataTable);
            if (command.CommandText == string.Empty)
            {
              return;
            }

            var flag = new AssertFlag();
            dataTable.EachRow(row =>
              {
                var first = flag.AssertTrue();
                ProcessCommandParameters(dataTable, command, row, first);
                command.ExecuteNonQuery();
              });
          }
          transcation.Commit();
        }
        catch (Exception exp)
        {
          if (transcation != null)
          {
            transcation.Rollback();
          }
          throw new BatcherException(exp);
        }
        finally
        {
          connection.TryClose();
        }
      }
    }

    private void ProcessCommandParameters(DataTable dataTable, DbCommand command, DataRow row, bool first)
    {
      for (var c = 0; c < dataTable.Columns.Count; c++)
      {
        DbParameter parameter;
        //首次創(chuàng)建參數(shù)，是為了使用緩存
        if (first)
        {
          parameter = ServiceContext.Database.Provider.DbProviderFactory.CreateParameter();
          parameter.ParameterName = dataTable.Columns[c].ColumnName;
          command.Parameters.Add(parameter);
        }
        else
        {
          parameter = command.Parameters[c];
        }
        parameter.Value = row[c];
      }
    }

    /// <summary>
    /// 生成插入數(shù)據(jù)的sql語句。
    /// </summary>
    /// <param name="database"></param>
    /// <param name="table"></param>
    /// <returns></returns>
    private string GenerateInserSql(IDatabase database, DataTable table)
    {
      var syntax = database.Provider.GetService<ISyntaxProvider>();
      var names = new StringBuilder();
      var values = new StringBuilder();
      var flag = new AssertFlag();
      table.EachColumn(column =>
        {
          if (!flag.AssertTrue())
          {
            names.Append(",");
            values.Append(",");
          }
          names.Append(DbUtility.FormatByQuote(syntax, column.ColumnName));
          values.AppendFormat("{0}{1}", syntax.ParameterPrefix, column.ColumnName);
        });
      return string.Format("INSERT INTO {0}({1}) VALUES ({2})", DbUtility.FormatByQuote(syntax, table.TableName), names, values);
    }
  }

四、MySql數(shù)據(jù)批量插入

/// <summary>
  /// 為 MySql.Data 組件提供的用于批量操作的方法。
  /// </summary>
  public sealed class MySqlBatcher : IBatcherProvider
  {
    /// <summary>
    /// 獲取或設(shè)置提供者服務(wù)的上下文。
    /// </summary>
    public ServiceContext ServiceContext { get; set; }

    /// <summary>
    /// 將 <see cref="DataTable"/> 的數(shù)據(jù)批量插入到數(shù)據(jù)庫中。
    /// </summary>
    /// <param name="dataTable">要批量插入的 <see cref="DataTable"/>。</param>
    /// <param name="batchSize">每批次寫入的數(shù)據(jù)量。</param>
    public void Insert(DataTable dataTable, int batchSize = 10000)
    {
      Checker.ArgumentNull(dataTable, "dataTable");
      if (dataTable.Rows.Count == 0)
      {
        return;
      }
      using (var connection = ServiceContext.Database.CreateConnection())
      {
        try
        {
          connection.TryOpen();
          using (var command = ServiceContext.Database.Provider.DbProviderFactory.CreateCommand())
          {
            if (command == null)
            {
              throw new BatcherException(new ArgumentException("command"));
            }
            command.Connection = connection;

            command.CommandText = GenerateInserSql(ServiceContext.Database, command, dataTable);
            if (command.CommandText == string.Empty)
            {
              return;
            }
            command.ExecuteNonQuery();
          }
        }
        catch (Exception exp)
        {
          throw new BatcherException(exp);
        }
        finally
        {
          connection.TryClose();
        }
      }
    }

    /// <summary>
    /// 生成插入數(shù)據(jù)的sql語句。
    /// </summary>
    /// <param name="database"></param>
    /// <param name="command"></param>
    /// <param name="table"></param>
    /// <returns></returns>
    private string GenerateInserSql(IDatabase database, DbCommand command, DataTable table)
    {
      var names = new StringBuilder();
      var values = new StringBuilder();
      var types = new List<DbType>();
      var count = table.Columns.Count;
      var syntax = database.Provider.GetService<ISyntaxProvider>();
      table.EachColumn(c =>
        {
          if (names.Length > 0)
          {
            names.Append(",");
          }
          names.AppendFormat("{0}", DbUtility.FormatByQuote(syntax, c.ColumnName));
          types.Add(c.DataType.GetDbType());
        });

      var i = 0;
      foreach (DataRow row in table.Rows)
      {
        if (i > 0)
        {
          values.Append(",");
        }
        values.Append("(");
        for (var j = 0; j < count; j++)
        {
          if (j > 0)
          {
            values.Append(", ");
          }
          var isStrType = IsStringType(types[j]);
          var parameter = CreateParameter(database.Provider, isStrType, types[j], row[j], syntax.ParameterPrefix, i, j);
          if (parameter != null)
          {
            values.Append(parameter.ParameterName);
            command.Parameters.Add(parameter);
          }
          else if (isStrType)
          {
            values.AppendFormat("'{0}'", row[j]);
          }
          else
          {
            values.Append(row[j]);
          }
        }
        values.Append(")");
        i++;
      }
      return string.Format("INSERT INTO {0}({1}) VALUES {2}", DbUtility.FormatByQuote(syntax, table.TableName), names, values);
    }

    /// <summary>
    /// 判斷是否為字符串類別。
    /// </summary>
    /// <param name="dbType"></param>
    /// <returns></returns>
    private bool IsStringType(DbType dbType)
    {
      return dbType == DbType.AnsiString || dbType == DbType.AnsiStringFixedLength || dbType == DbType.String || dbType == DbType.StringFixedLength;
    }

    /// <summary>
    /// 創(chuàng)建參數(shù)。
    /// </summary>
    /// <param name="provider"></param>
    /// <param name="isStrType"></param>
    /// <param name="dbType"></param>
    /// <param name="value"></param>
    /// <param name="parPrefix"></param>
    /// <param name="row"></param>
    /// <param name="col"></param>
    /// <returns></returns>
    private DbParameter CreateParameter(IProvider provider, bool isStrType, DbType dbType, object value, char parPrefix, int row, int col)
    {
      //如果生成全部的參數(shù)，則速度會很慢，因此，只有數(shù)據(jù)類型為字符串(包含'號)和日期型時才添加參數(shù)
      if ((isStrType && value.ToString().IndexOf('\'') != -1) || dbType == DbType.DateTime)
      {
        var name = string.Format("{0}p_{1}_{2}", parPrefix, row, col);
        var parameter = provider.DbProviderFactory.CreateParameter();
        parameter.ParameterName = name;
        parameter.Direction = ParameterDirection.Input;
        parameter.DbType = dbType;
        parameter.Value = value;
        return parameter;
      }
      return null;
    }
  }

MySql的批量插入，是將值全部寫在語句的values里，例如，insert batcher(id, name) values(1, '1', 2, '2', 3, '3', ........ 10, '10')。

五、測試

接下來寫一個測試用例來看一下使用批量插入的效果。

 public void TestBatchInsert()
    {
      Console.WriteLine(TimeWatcher.Watch(() =>
        InvokeTest(database =>
          {
            var table = new DataTable("Batcher");
            table.Columns.Add("Id", typeof(int));
            table.Columns.Add("Name1", typeof(string));
            table.Columns.Add("Name2", typeof(string));
            table.Columns.Add("Name3", typeof(string));
            table.Columns.Add("Name4", typeof(string));

            //構(gòu)造100000條數(shù)據(jù)
            for (var i = 0; i < 100000; i++)
            {
              table.Rows.Add(i, i.ToString(), i.ToString(), i.ToString(), i.ToString());
            }

            //獲取 IBatcherProvider
            var batcher = database.Provider.GetService<IBatcherProvider>();
            if (batcher == null)
            {
              Console.WriteLine("不支持批量插入。");
            }
            else
            {
              batcher.Insert(table);
            }

            //輸出batcher表的數(shù)據(jù)量
            var sql = new SqlCommand("SELECT COUNT(1) FROM Batcher");
            Console.WriteLine("當(dāng)前共有 {0} 條數(shù)據(jù)", database.ExecuteScalar(sql));

          })));
    }

以下表中列出了四種數(shù)據(jù)庫生成10萬條數(shù)據(jù)各耗用的時間