/// <summary>获取数据抽取器。优先自增，默认分页</summary>
/// <param name="table"></param>
/// <returns></returns>
protected virtual IExtracter <DbTable> GetExtracter(IDataTable table)
{
// 自增
var id = table.Columns.FirstOrDefault(e => e.Identity);
if (id == null)
{
var pks = table.PrimaryKeys;
if (pks != null && pks.Length == 1 && pks[0].DataType.IsInt())
{
id = pks[0];
}
}
var tableName = Dal.Db.FormatName(table);
IExtracter <DbTable> extracer;
var pk = table.Columns.FirstOrDefault(e => e.PrimaryKey);
// 兼容SqlServer2008R2分页功能
if (pk == null || Dal.DbType == DatabaseType.SqlServer)
{
var dc = table.Columns.FirstOrDefault();
extracer = new PagingExtracter(Dal, tableName, dc.ColumnName);
}
else
{
extracer = new PagingExtracter(Dal, tableName);
}
if (id != null)
{
extracer = new IdExtracter(Dal, tableName, id.ColumnName);
}
return(extracer);
}
/// <summary>获取数据抽取器。优先自增，默认分页</summary>
/// <param name="table"></param>
/// <returns></returns>
protected virtual IExtracter <DbTable> GetExtracter(IDataTable table)
{
// 自增
var id = table.Columns.FirstOrDefault(e => e.Identity);
if (id == null)
{
var pks = table.PrimaryKeys;
if (pks != null && pks.Length == 1 && pks[0].DataType.IsInt())
{
id = pks[0];
}
}
var tableName = Dal.Db.FormatName(table);
IExtracter <DbTable> extracer = new PagingExtracter(Dal, tableName);
if (id != null)
{
extracer = new IdExtracter(Dal, tableName, id.ColumnName);
}
return(extracer);
}
/// <summary>备份单表数据</summary>
/// <remarks>
/// 最大支持21亿行
/// </remarks>
/// <param name="table">数据表</param>
/// <param name="stream">目标数据流</param>
/// <param name="progress">进度回调，参数为已处理行数和当前页表</param>
/// <returns></returns>
public Int32 Backup(IDataTable table, Stream stream, Action <Int64, DbTable> progress = null)
{
var writeFile = new WriteFileActor
{
Stream = stream,
// 最多同时堆积数
BoundedCapacity = 4,
};
// 自增
var id = table.Columns.FirstOrDefault(e => e.Identity);
if (id == null)
{
var pks = table.PrimaryKeys;
if (pks != null && pks.Length == 1 && pks[0].DataType.IsInt())
{
id = pks[0];
}
}
var tableName = Db.FormatName(table);
var sb = new SelectBuilder {
Table = tableName
};
// 总行数
writeFile.Total = SelectCount(sb);
WriteLog("备份[{0}/{1}]开始，共[{2:n0}]行", table, ConnName, writeFile.Total);
IExtracter <DbTable> extracer = new PagingExtracter(this, tableName);
if (id != null)
{
extracer = new IdExtracter(this, tableName, id.ColumnName);
}
var sw = Stopwatch.StartNew();
var total = 0;
foreach (var dt in extracer.Fetch())
{
var count = dt.Rows.Count;
WriteLog("备份[{0}/{1}]数据 {2:n0} + {3:n0}", table, ConnName, extracer.Row, count);
if (count == 0)
{
break;
}
// 进度报告
progress?.Invoke(extracer.Row, dt);
// 消费数据
writeFile.Tell(dt);
total += count;
}
// 通知写入完成
writeFile.Stop(-1);
sw.Stop();
var ms = sw.Elapsed.TotalMilliseconds;
WriteLog("备份[{0}/{1}]完成，共[{2:n0}]行，耗时{3:n0}ms，速度{4:n0}tps", table, ConnName, total, ms, total * 1000L / ms);
// 返回总行数
return(total);
}
