关于 SqlServer 批量插入的方式，前段时间也有大神给出了好几种批量插入的方式及对比测试（http://www.cnblogs.com/jiekzou/p/6145550.html），估计大家也都明白，最佳的方式就是用 SqlBulkCopy。我对 SqlBulkCopy 封装成了一个 Helper 方法，使得批量插入更加方便，先看看封装后的方法定义：
public static class SqlConnectionExtension
{
/// <summary>
/// 使用 SqlBulkCopy 向 destinationTableName 表插入数据
/// </summary>
/// <typeparam name="TModel">必须拥有与目标表所有字段对应属性</typeparam>
/// <param name="conn"></param>
/// <param name="modelList">要插入的数据</param>
/// <param name="batchSize">SqlBulkCopy.BatchSize</param>
/// <param name="destinationTableName">如果为 null，则使用 TModel 名称作为 destinationTableName</param>
/// <param name="bulkCopyTimeout">SqlBulkCopy.BulkCopyTimeout</param>
/// <param name="externalTransaction">要使用的事务</param>
public static void BulkCopy<TModel>(this SqlConnection conn, List<TModel> modelList, int batchSize, string destinationTableName = null, int? bulkCopyTimeout = null, SqlTransaction externalTransaction = null);
}
上面都有详细解释，相信大家一看就会明白，接下来演示下用法及效果：
先创建一个测试的 Users 表：
CREATE TABLE [dbo].[Users](
[Id] [uniqueidentifier] NOT NULL,
[Name] [nvarchar](100) NULL,
[Gender] [int] NULL,
[Age] [int] NULL,
[CityId] [int] NULL,
[OpTime] [datetime] NULL,
CONSTRAINT [PK_Users] PRIMARY KEY CLUSTERED([Id] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
然后定义一个与表映射的 Model，记住，由于 SqlBulkCopy 的特性，定义的 Model 必须拥有与表所有的字段对应的属性：
public enum Gender
{
Man = 1,
Woman
}
public class User
{
public Guid Id { get; set; }
public string Name { get; set; }
public Gender? Gender { get; set; }
public int? Age { get; set; }
public int? CityId { get; set; }
public DateTime? OpTime { get; set; }
}
制造些数据，然后就可以直接插入了：
List<User> usersToInsert = new List<User>();
usersToInsert.Add(new User() { Id = Guid.NewGuid(), Name = "so1", Gender = Gender.Man, Age = 18, CityId = 1, OpTime = DateTime.Now });
usersToInsert.Add(new User() { Id = Guid.NewGuid(), Name = "so2", Gender = Gender.Man, Age = 19, CityId = 2, OpTime = DateTime.Now });
usersToInsert.Add(new User() { Id = Guid.NewGuid(), Name = "so3", Gender = Gender.Man, Age = 20, CityId = 3, OpTime = DateTime.Now });
usersToInsert.Add(new User() { Id = Guid.NewGuid(), Name = "so4", Gender = Gender.Man, Age = 21, CityId = 4, OpTime = DateTime.Now });
using (SqlConnection conn = new SqlConnection("Data Source = .;Initial Catalog = Chloe;Integrated Security = SSPI;"))
{
conn.BulkCopy(usersToInsert, 20000, "Users");
}
执行插入后表数据：
很方便吧，定义好 Model，调用 BulkCopy 方法就能插入了。这个方法主要解决了两个问题：1.免去手动构造 DataTable 和向 DataTable 填充数据，要知道，SqlBulkCopy 要求 DataTable 的列必须和表列顺序一致，如果手动构造 DataTable 的话会使代码很难维护；2.不用亲自 new 出 SqlBulkCopy 对象以及手动给 SqlBulkCopy 对象设置各种值，如 DestinationTableName、BulkCopyTimeout、BatchSize 等，用封装的方法，直接传相应的值就好了。接下来贴干货，简单介绍下实现。
先了解 SqlBulkCopy 的定义（部分）：
public sealed class SqlBulkCopy : IDisposable
{
public SqlBulkCopy(SqlConnection connection);
public SqlBulkCopy(string connectionString);
public SqlBulkCopy(string connectionString, SqlBulkCopyOptions copyOptions);
public SqlBulkCopy(SqlConnection connection, SqlBulkCopyOptions copyOptions, SqlTransaction externalTransaction);
public int BatchSize { get; set; }
public int BulkCopyTimeout { get; set; }
public SqlBulkCopyColumnMappingCollection ColumnMappings { get; }
public string DestinationTableName { get; set; }
public bool EnableStreaming { get; set; }
public int NotifyAfter { get; set; }
public event SqlRowsCopiedEventHandler SqlRowsCopied;
public void Close();
public void WriteToServer(DataRow[] rows);
public void WriteToServer(DataTable table);
public void WriteToServer(IDataReader reader);
public void WriteToServer(DataTable table, DataRowState rowState);
}
我们只需关注 WriteToServer 方法。因为我们的数据源不是数据库或excel，所以我们直接不考虑 WriteToServer(IDataReader reader)。WriteToServer(DataRow[] rows) 直接无视，不多解释，所以我们只需考虑用 WriteToServer(DataTable table) 就行了。开干！
一、构造一个结构严谨的 DataTable。
由于 SqlBulkCopy 要求 DataTable 的列必须和表列顺序一致，并且不能多也不能少，所以，我们首先要创建一个和目标表字段顺序一致的 DataTable，先查出目标表的结构：
static List<SysColumn> GetTableColumns(SqlConnection sourceConn, string tableName)
{
string sql = string.Format("select * from syscolumns inner join sysobjects on syscolumns.id=sysobjects.id where sysobjects.xtype='U' and sysobjects.name='{0}' order by syscolumns.colid asc", tableName);
List<SysColumn> columns = new List<SysColumn>();
using (SqlConnection conn = (SqlConnection)((ICloneable)sourceConn).Clone())
{
conn.Open();
using (var reader = conn.ExecuteReader(sql))
{
while (reader.Read())
{
SysColumn column = new SysColumn();
column.Name = reader.GetDbValue("name");
column.ColOrder = reader.GetDbValue("colorder");
columns.Add(column);
}
}
conn.Close();
}
return columns;
}
得到基本的表结构 List
DataTable dt = new DataTable();
Type modelType = typeof(TModel);
List<SysColumn> columns = GetTableColumns(conn, tableName);
List<PropertyInfo> mappingProps = new List<PropertyInfo>();
var props = modelType.GetProperties();
for (int i = 0; i < columns.Count; i++)
{
var column = columns[i];
PropertyInfo mappingProp = props.Where(a => a.Name == column.Name).FirstOrDefault();
if (mappingProp == null)
throw new Exception(string.Format("model 类型 '{0}'未定义与表 '{1}' 列名为 '{2}' 映射的属性", modelType.FullName, tableName, column.Name));
mappingProps.Add(mappingProp);
Type dataType = GetUnderlyingType(mappingProp.PropertyType);
if (dataType.IsEnum)
dataType = typeof(int);
dt.Columns.Add(new DataColumn(column.Name, dataType));
}
注意，构造 DataColumn 时，要给 Column 设置 DataType，及数据类型。因为如果不指定数据类型，默认是 string 类型，那样会导致将数据发送至数据库时会引起数据转换，会有些许无谓的性能损耗，同时，如果不指定数据类型，导入一些数据类型时可能会失败，比如模型属性是 Guid 类型，导入时会出现类型转换失败异常。
二、利用反射，获取属性值，构造一行一行的 DataRow，填充 DataTable：
foreach (var model in modelList)
{
DataRow dr = dt.NewRow();
for (int i = 0; i < mappingProps.Count; i++)
{
PropertyInfo prop = mappingProps[i];
object value = prop.GetValue(model);
if (GetUnderlyingType(prop.PropertyType).IsEnum)
{
if (value != null)
value = (int)value;
}
dr[i] = value ?? DBNull.Value;
}
dt.Rows.Add(dr);
}
三、一个完整包含数据的 DataTable 对象就创建好了，我们就可以使用 SqlBulkCopy 插入数据了：
public static void BulkCopy<TModel>(this SqlConnection conn, List<TModel> modelList, int batchSize, string destinationTableName = null, int? bulkCopyTimeout = null, SqlTransaction externalTransaction = null)
{
bool shouldCloseConnection = false;
if (string.IsNullOrEmpty(destinationTableName))
destinationTableName = typeof(TModel).Name;
DataTable dtToWrite = ToSqlBulkCopyDataTable(modelList, conn, destinationTableName);
SqlBulkCopy sbc = null;
try
{
if (externalTransaction != null)
sbc = new SqlBulkCopy(conn, SqlBulkCopyOptions.Default, externalTransaction);
else
sbc = new SqlBulkCopy(conn);
using (sbc)
{
sbc.BatchSize = batchSize;
sbc.DestinationTableName = destinationTableName;
if (bulkCopyTimeout != null)
sbc.BulkCopyTimeout = bulkCopyTimeout.Value;
if (conn.State != ConnectionState.Open)
{
shouldCloseConnection = true;
conn.Open();
}
sbc.WriteToServer(dtToWrite);
}
}
finally
{
if (shouldCloseConnection && conn.State == ConnectionState.Open)
conn.Close();
}
}
完事，一个批量插入的 Helper 方法就这么产生了，最终的完整实现如下：
public static class SqlConnectionExtension
{
/// <summary>
/// 使用 SqlBulkCopy 向 destinationTableName 表插入数据
/// </summary>
/// <typeparam name="TModel">必须拥有与目标表所有字段对应属性</typeparam>
/// <param name="conn"></param>
/// <param name="modelList">要插入的数据</param>
/// <param name="batchSize">SqlBulkCopy.BatchSize</param>
/// <param name="destinationTableName">如果为 null，则使用 TModel 名称作为 destinationTableName</param>
/// <param name="bulkCopyTimeout">SqlBulkCopy.BulkCopyTimeout</param>
/// <param name="externalTransaction">要使用的事务</param>
public static void BulkCopy<TModel>(this SqlConnection conn, List<TModel> modelList, int batchSize, string destinationTableName = null, int? bulkCopyTimeout = null, SqlTransaction externalTransaction = null)
{
bool shouldCloseConnection = false;
if (string.IsNullOrEmpty(destinationTableName))
destinationTableName = typeof(TModel).Name;
DataTable dtToWrite = ToSqlBulkCopyDataTable(modelList, conn, destinationTableName);
SqlBulkCopy sbc = null;
try
{
if (externalTransaction != null)
sbc = new SqlBulkCopy(conn, SqlBulkCopyOptions.Default, externalTransaction);
else
sbc = new SqlBulkCopy(conn);
using (sbc)
{
sbc.BatchSize = batchSize;
sbc.DestinationTableName = destinationTableName;
if (bulkCopyTimeout != null)
sbc.BulkCopyTimeout = bulkCopyTimeout.Value;
if (conn.State != ConnectionState.Open)
{
shouldCloseConnection = true;
conn.Open();
}
sbc.WriteToServer(dtToWrite);
}
}
finally
{
if (shouldCloseConnection && conn.State == ConnectionState.Open)
conn.Close();
}
}
public static DataTable ToSqlBulkCopyDataTable<TModel>(List<TModel> modelList, SqlConnection conn, string tableName)
{
DataTable dt = new DataTable();
Type modelType = typeof(TModel);
List<SysColumn> columns = GetTableColumns(conn, tableName);
List<PropertyInfo> mappingProps = new List<PropertyInfo>();
var props = modelType.GetProperties();
for (int i = 0; i < columns.Count; i++)
{
var column = columns[i];
PropertyInfo mappingProp = props.Where(a => a.Name == column.Name).FirstOrDefault();
if (mappingProp == null)
throw new Exception(string.Format("model 类型 '{0}'未定义与表 '{1}' 列名为 '{2}' 映射的属性", modelType.FullName, tableName, column.Name));
mappingProps.Add(mappingProp);
Type dataType = GetUnderlyingType(mappingProp.PropertyType);
if (dataType.IsEnum)
dataType = typeof(int);
dt.Columns.Add(new DataColumn(column.Name, dataType));
}
foreach (var model in modelList)
{
DataRow dr = dt.NewRow();
for (int i = 0; i < mappingProps.Count; i++)
{
PropertyInfo prop = mappingProps[i];
object value = prop.GetValue(model);
if (GetUnderlyingType(prop.PropertyType).IsEnum)
{
if (value != null)
value = (int)value;
}
dr[i] = value ?? DBNull.Value;
}
dt.Rows.Add(dr);
}
return dt;
}
static List<SysColumn> GetTableColumns(SqlConnection sourceConn, string tableName)
{
string sql = string.Format("select * from syscolumns inner join sysobjects on syscolumns.id=sysobjects.id where sysobjects.xtype='U' and sysobjects.name='{0}' order by syscolumns.colid asc", tableName);
List<SysColumn> columns = new List<SysColumn>();
using (SqlConnection conn = (SqlConnection)((ICloneable)sourceConn).Clone())
{
conn.Open();
using (var reader = conn.ExecuteReader(sql))
{
while (reader.Read())
{
SysColumn column = new SysColumn();
column.Name = reader.GetDbValue("name");
column.ColOrder = reader.GetDbValue("colorder");
columns.Add(column);
}
}
conn.Close();
}
return columns;
}
static Type GetUnderlyingType(Type type)
{
Type unType = Nullable.GetUnderlyingType(type); ;
if (unType == null)
unType = type;
return unType;
}
class SysColumn
{
public string Name { get; set; }
public int ColOrder { get; set; }
}
}
完整代码
代码不多，仅仅150行，大家可以直接拷走拿去用。其中用了反射，估计吃瓜群众可能不淡定了~哈哈，如果你真有大数据插入需求，这点反射消耗相对大数据插入简直九牛一毛，微乎其微，放心好了。
