[英]DataAdapter : if row already exist, then update, else insert
我有一个带有本地SQL CE数据库的Windows Mobile PPC,我试图在连接时将其复制到远程SQL Server数据库。 我不能使用批量复制或任何其他“自动化”方法,因为该平台已经过时并且SQL CE受到限制。
我在这里采用了一个解决方案,但是我有点迷茫,因为该过程在目标数据库为空时运行良好,但是在它具有预先存在的数据时会失败(主键错误)。 因此,DataAdapter可能仅进行插入,而不能进行更新。
这是我的代码:
private void StockSqlBuilder()
{
DataSet SqlCeDataset = new DataSet("source");
DataSet SqlDataset = new DataSet("destination");
try
{
_conn.Open();
// Pull data from local database SQLCE
using (SqlCeDataAdapter sourceDA = new SqlCeDataAdapter("SELECT * FROM stock", _conn))
{
MessageBox.Show("Pull Stock from CE");
sourceDA.Fill(SqlCeDataset, "stock");
}
_conn.Close();
_remoteConn.Open();
// Connect to SQL Server database to push data
using (SqlDataAdapter destinationDA = new SqlDataAdapter("SELECT * FROM stock", _remoteConn))
{
// Get table of remote SQL Server, then loop through all rows of SQLCE and add them to dataset
SqlCommandBuilder cmdBuilder = new SqlCommandBuilder(destinationDA);
destinationDA.Fill(SqlDataset, "stock");
foreach (DataRow row in SqlCeDataset.Tables["stock"].Rows)
{
SqlDataset.Tables[0].NewRow();
SqlDataset.Tables[0].Rows.Add(row.ItemArray);
}
destinationDA.Update(SqlDataset, "stock");
}
_remoteConn.Close();
}
catch (SqlException Sqlex)
{
MessageBox.Show(Sqlex.Message);
this.returnStatus = false;
}
catch (SqlCeException SqlCEex)
{
MessageBox.Show(SqlCEex.Message);
this.returnStatus = false;
}
}
另外,如果您对我的项目有双向SQL同步的其他解决方案,我会不胜枚举,但我尝试了很多不同的方法。
使用临时表进行合并查询并比较选择性更新的日期,可获得良好的结果:
string mergeQuery = @"--Synchronize the target table with refreshed data from source table
MERGE dbo.stock AS TARGET
USING dbo.stock_sync AS SOURCE
ON (TARGET.product_id = SOURCE.product_id)
--When records are matched, update the records if there is any change
WHEN MATCHED AND SOURCE.date_stock > TARGET.date_stock THEN
UPDATE SET TARGET.spot= SOURCE.spot,
TARGET.date_stock = SOURCE.date_stock,
TARGET.loading_id = SOURCE.loading_id
--When no records are matched, insert the incoming records from source table to target table
WHEN NOT MATCHED BY TARGET THEN
INSERT (spot, product_id, date_stock, loading_id)
VALUES (SOURCE.spot, SOURCE.product_id, SOURCE.date_stock, SOURCE.loading_id);
SELECT * FROM dbo.stock;";
// Merge the two tables by matching code_barre row
SqlCommand mergeSql = new SqlCommand(mergeQuery, _remoteConn);
int rowsAffected = mergeSql.ExecuteNonQuery();
MessageBox.Show("Données affectées : " + rowsAffected);
// Clean the temporary source table
SqlCommand recleanSql = new SqlCommand("TRUNCATE TABLE dbo.stock_sync", _remoteConn);
recleanSql.ExecuteNonQuery();
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