内外网数据库同步方式「建议收藏」

项目环境：公司中心有一个数据库，产品部署地有多个，每个部署地是一个局域网，部署地内有一台对外通讯的服务器(可能会断网)。项目需要将每个部署地的部分数据，同步到中心数据库。

基本思路：在需要同步的数据库的说明中添加Update标识，在需要同步的表中添加UpdateDate字段。在每一天的0点时候，会执行一次同步，根据UpdateDate字段进行时间比对，同步会遍历当前数据库的所以后表，如果表中包含Update标识，就执行同步操作。同步时执行事务操作，全部数据同步完成后进行提交操作。如果有错误，则执行RollBack，并发送邮件通知维护人员。

本地数据库LocalDB

远端数据库RemoteDB

表名 TableName

主键PrimaryKey

简要步奏

0. BeginTrans

LocalDB：

1 从LocalDB读出DateTable

RemoteDB：

2. 数据库使用select * into tmpTable from TableName where PrimaryKey=-1 生成临时表

3. 将数据集提交到临时表中

4.

—更新相同数据 / 删除相同数据 二选一即可

–更新(需要对知道每个表的哪些字段需要更新)

update TableName set CreateDate=A.CreateDate from tmpTable A,TableName B where B.PrimaryKey=A.PrimaryKey

–删除

delete from TableName where PrimaryKey in (select PrimaryKey from tmpTable)

—插入不同数据的记录

insert into TableName select * from tmpTable A where not exists(select PrimaryKey from TableName B where B.{1}=A.PrimaryKey )

5. 跳到第一步 直到所有表都更新完成

6. Commit

<code style="margin-left:0">public class Base_TableUpdate
{
public int Run(DateTime lastUpdateDate)
{
IDatabase dbRemote = null;
int updateCount = 0;
try
{
IDatabase dbLocal = DataFactory.Database("LocalSqlServer");
dbRemote = DataFactory.Database("RemoteSqlServer");
DbTransaction trans = dbRemote.BeginTrans();
//查询出所有表
/*
select
ROW_NUMBER() OVER (ORDER BY a.object_id) AS No, 
a.name AS TableName,
isnull(g.[value],'') AS Explain
from
sys.tables a left join sys.extended_properties g
on (a.object_id = g.major_id AND g.minor_id = 0)
*/
string sql = string.Format("select ROW_NUMBER() OVER (ORDER BY a.object_id) AS No, a.name AS TableName, isnull(g.[value],'') AS Explain  from sys.tables a left join sys.extended_properties g on (a.object_id = g.major_id AND g.minor_id = 0)");
List<TableNameEntity> list = dbLocal.FindListBySql<TableNameEntity>(sql);
foreach(TableNameEntity en in list)
{
if (string.IsNullOrEmpty(en.Explain) || !en.Explain.ToLower().Contains("update"))
continue;
string tableName = en.TableName;
//1 查出数据
//where UpdateDate>'{1}'
DataSet ds = dbLocal.FindDataSetBySql(string.Format("select * from {0} where UpdateDate>'{1}'", tableName, lastUpdateDate.ToString("yyyy-MM-dd hh:mm:ss")));
updateCount += ds.Tables[0].Rows.Count;
//2 创建临时表
int res = dbRemote.FindCountBySql("select Count(Name) from sysobjects where name='tmpTable'");
if (res == -1)
{//失败
throw new Exception("10001 查询临时表时失败，Code{ dbLocal.FindCountBySql(\"select Count(Name) from sysobjects where name='tmpTable'\"); }");
}
else if (res == 1)
{//表存在,删除表
dbRemote.ExecuteBySql(new StringBuilder("Drop Table tmpTable"));
}
//创建
StringBuilder sb = new StringBuilder();
sb.AppendFormat("select * into tmpTable from {0} where (SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME='{0}') is null", tableName);
res = dbRemote.ExecuteBySql(sb);
if (res == -1)
{
throw new Exception("10002 创建临时表时失败，Code{ sb.AppendFormat(\"select * into tmpTable from {0} where (SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME='{0}') is null\", tableName);dbRemote.ExecuteBySql(sb); }");
}
//3 往临时表插入数据
//获得表主键
sb = new StringBuilder();
sb.AppendFormat("SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME='{0}'", tableName);
PrimaryKeyEntity entity = dbRemote.FindEntityBySql<PrimaryKeyEntity>(sb.ToString());
string primaryKey = entity.COLUMN_NAME;
if (string.IsNullOrEmpty(primaryKey))
{
string errmsg = string.Format("10006 表主键为空，Code{ sb.AppendFormat(\"SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME='{0}'\", tableName); } Parameter{ tableName:{0}}", tableName);
throw new Exception(errmsg);
}
//插入所有数据
ds.Tables[0].TableName = "tmpTable";
bool bInRes = dbRemote.BulkInsert(ds.Tables[0], trans);
if (!bInRes)
{
string errmsg = string.Format("10003 插入所有数据时失败，Code{ ds.Tables[0].TableName = \"tmpTable\";bool bInRes = dbRemote.BulkInsert(ds.Tables[0], trans); }");
throw new Exception(errmsg);
}
//4 合并临时表与服务器对应表数据
//删除已有数据
//delete from ' + @TableName + ' where ' + @PKey + ' in (select ' + @PKey + ' from tmpTable)
sb = new StringBuilder();
sb.AppendFormat("delete from {0} where {1} in (select {1} from tmpTable)", tableName, primaryKey);
res = dbRemote.ExecuteBySql(sb, trans);
if (res == -1)
{
string errmsg = string.Format("10004 删除已有数据时失败，Code{ sb.AppendFormat(\"delete from {0} where {1} in (select {1} from tmpTable)\", tableName, primaryKey);res =dbRemote.ExecuteBySql(sb); } Parameter{ tableName:{0}, primaryKey:{1}}", tableName, primaryKey);
throw new Exception(errmsg);
}
//将数据插入表
//insert into tmpTable select * from ' + @TableName + ' A where not exists(select ' + @PKey + ' from tmpTable B where B.' + @PKey + '=A.' + @PKey + ')';
sb = new StringBuilder();
sb.AppendFormat("insert into {0} select * from tmpTable A where not exists(select {1} from {0} B where B.{1}=A.{1})", tableName, primaryKey);
res = dbRemote.ExecuteBySql(sb, trans);
if (res == -1)
{
string errmsg = string.Format("10005 合并数据时失败，Code{ sb.AppendFormat(\"insert into {0} select * from tmpTable A where not exists(select {1} from {0} B where B.{1}=A.{1})\", tableName, primaryKey);res = dbRemote.ExecuteBySql(sb); } Parameter{ tableName:{0}, primaryKey:{1}}", tableName, primaryKey);
throw new Exception(errmsg);
}
//5 删除临时表
dbRemote.ExecuteBySql(new StringBuilder("Drop Table tmpTable"));
}
dbRemote.Commit();
return updateCount;
}
catch(Exception ex)
{
try{ dbRemote.Rollback(); } catch { }
throw ex;
}
}
}
public class PrimaryKeyEntity
{
private string _COLUMN_NAME;
/// <summary>
/// 表的主键名
/// </summary>
public string COLUMN_NAME
{
get { return _COLUMN_NAME; }
set { _COLUMN_NAME = value; }
}
}
public class TableNameEntity
{
private string _TableName;
public string TableName
{
get { return _TableName; }
set { _TableName = value; }
}
private string _Explain;
public string Explain
{
get { return _Explain; }
set { _Explain = value; }
}
}</code>

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