DownloadTableData 接口

语法

interface DownloadTableData

注释

为一个同步封装一个下载表的信息。使用此接口设置将被下载到同步客户端站点的数据操作。

示例

例如，假设您具有以下表：

CREATE TABLE remoteOrders (
    pk INT NOT NULL,
    col1 VARCHAR(200),
    PRIMARY KEY (pk)
);

以下示例使用 DownloadData.GetDownloadTableByName 方法返回表示 remoteOrders 表的 DownloadTableData 实例。

// The method used for the handle_DownloadData event
public void HandleDownload() {
    // _cc is a DBConnectionContext instance.

    // Get the DownloadData for the current synchronization.
    DownloadData my_dd = _cc.GetDownloadData();
 
    // Get the DownloadTableData for the remoteOrders table.
    DownloadTableData td = my_dd.GetDownloadTableByName("remoteOrders");

    // User defined-methods to set download operations.
    SetDownloadUpserts(td);
    SetDownloadDeletes(td); 

    // ... 
}

在本例中，SetDownloadInserts 方法使用 DownloadTableData.GetUpsertCommand 为您想要插入或更新的行获取命令。IDbCommand 将会保存一些参数，这些参数将会被设置为您要插入到远程数据库中的值。

void SetDownloadInserts(DownloadTableData td) { 
    IDbCommand  upsert_cmd = td.GetUpsertCommand();
    IDataParameterCollection parameters = upsert_cmd.Parameters;
    
    // The following method calls are the same as the following SQL statement:
    // INSERT INTO remoteOrders(pk, col1) values(2300, "truck");
    ((IDataParameter) (parameters[0])).Value = (Int32) 2300;
    ((IDataParameter) (parameters[1])).Value = (String) "truck";

    if (upsert_cmd.ExecuteNonQuery() > 0) {
        // Insert was not filtered.
    }
    else {
        // Insert was filtered because it was uploaded
        // in the same synchronization.
    }
 }

SetDownloadDeletes 方法使用 DownloadTableData.GetDeleteCommand 为您想要删除的行获取命令。

void SetDownloadDeletes(DownloadTableData td) { 
    IDbCommand  delete_cmd = t2_download_dd.GetDeleteCommand();

    // The following method calls are the same as the following SQL statement:
    // DELETE FROM remoteOrders  where pk = 2300;
    IDataParameterCollection parameters = delete_cmd.Parameters;
    ((IDataParameter) (parameters[0])).Value = (Int32) 2300;
    delete_cmd.ExecuteNonQuery();
}

GetDeleteCommand 方法
 GetLastDownloadTime 方法
 GetName 方法
 GetSchemaTable 方法
 GetUpsertCommand 方法