c# - 在数据库之间复制表

Question

假设我想将所有表及其完整数据从一个数据库复制到另一个数据库，而无需特别了解有关它们的详细信息(列数、数据类型...)。用户将向他的数据库输入一个连接字符串，并且来自它的所有数据都将被复制到一个内部数据库中。 我试图通过使用 SqlConnection 并编写直接的 T-SQL 查询来实现它，并设法编写了一个脚本，该脚本在内部数据库中创建具有正确列的空表:

string createDestinationTableQuery = "create table " + schemaName + ".[" + tableName + "](";
DataTable ColumnsDT = new DataTable();
string getTableColumnDataQuery = "SELECT * FROM "+originalDBName+".INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = N'" + tableName +"'";
SqlCommand getTableColumnDataCommand = new SqlCommand(getTableColumnDataQuery, originalCon);
SqlDataAdapter TableDA = new SqlDataAdapter(getTableColumnDataCommand);
TableDA.Fill(ColumnsDT);
for (int x = 0; x < ColumnsDT.Rows.Count; x++)
{
    createDestinationTableQuery += "[" + ColumnsDT.Rows[x].ItemArray[3].ToString() + "] " + "[" + ColumnsDT.Rows[x].ItemArray[7].ToString() + "], ";

}

createDestinationTableQuery = createDestinationTableQuery.Remove(createDestinationTableQuery.Length - 2);
createDestinationTableQuery += " )";

SqlCommand createDestinationTableCommand = new SqlCommand(createDestinationTableQuery, destinationCon);
createDestinationTableCommand.ExecuteNonQuery();
Console.WriteLine("Table " + schemaName + "." + tableName + " created succesfully!");

但是，我正在为数据插入而苦苦挣扎，因为以下代码根本不起作用:

DataTable dataTable = new DataTable();

string getTableDataquery = "select * from " + originalTableWithSchema;
SqlCommand getTableDataCommand = new SqlCommand(getTableDataquery, originalCon);
SqlDataAdapter da = new SqlDataAdapter(getTableDataCommand);

da.Fill(dataTable);

for (int x = 0; x < dataTable.Rows.Count; x++)
{
    string insertQuery = "insert into " + schemaName + ".["+tableName+"](" ;
    string values = "VALUES(";

    for (int y = 0; y < dataTable.Columns.Count; y++)
    {
        insertQuery += dataTable.Columns[y].ColumnName + ", ";
        values += dataTable.Rows[x].ItemArray[y].ToString() + ", ";
    }
    insertQuery = insertQuery.Remove(insertQuery.Length - 2);
    insertQuery += " )";
    values = values.Remove(values.Length - 2);
    values += " )";
    insertQuery += " " + values;
    SqlCommand insertCommand = new SqlCommand(insertQuery, destinationCon);
    insertCommand.ExecuteNonQuery();

}

da.Dispose();

我怎样才能正确实现这个功能？我在考虑是否可以放弃所有代码并改用 SMO？

Answer 1

如果您只想复制数据(因为您已经创建了结构)，那么您可以使用 DataTable 将数据保存在非 dbms 特定结构中，并使用 DataAdapter 生成特定于 dbms 的插入语句。这是我不久前编写的用于将数据从 Access 复制到 MySQL 的代码的摘录:

List<string> tableNames = new List<string>();
try
{
    // Open connect to access db
    sourceConn.Open();
    // Build table names list from schema
    foreach (DataRow row in sourceConn.GetSchema("Tables").Select("table_type = 'TABLE'"))
        tableNames.Add(row["table_name"].ToString());                
}
catch (Exception ex)
{
    throw ex;
}
finally
{
    if(sourceConn.State != ConnectionState.Closed)
        sourceConn.Close();
}

foreach (string table in tableNames)
{
    //Get all table data from Access
    string query = string.Format("SELECT * FROM {0}", table);
    DataTable accessTable = new DataTable(table);
    try
    {
        sourceConn.Open();
        System.Data.OleDb.OleDbCommand accessSqlCommand = new System.Data.OleDb.OleDbCommand(query, accessConn);
        System.Data.OleDb.OleDbDataReader reader = (System.Data.OleDb.OleDbDataReader)accessSqlCommand.ExecuteReader();
        // Load all table data into accessTable
        accessTable.Load(reader);
    }
    catch(Exception ex)
    {
        throw ex;
    }
    finally
    {
        if(sourceConn.State != ConnectionState.Closed)
            sourceConn.Close();
    }

    // Import data into MySQL
    accessTable.AcceptChanges();
    // The table should be empty, so set everything as new rows (will be inserted)
    foreach (DataRow row in accessTable.Rows)
        row.SetAdded();

    try
    {
        destConn.Open();
        MySql.Data.MySqlClient.MySqlDataAdapter da = new MySql.Data.MySqlClient.MySqlDataAdapter(query, mySqlConn);
        MySql.Data.MySqlClient.MySqlCommandBuilder cb = new MySql.Data.MySqlClient.MySqlCommandBuilder(da);
        da.InsertCommand = cb.GetInsertCommand();

        // Update the destination table 128 rows at a time
        da.UpdateBatchSize = 128;

        // Perform inserts (and capture row counts for output)
        int insertCount = da.Update(accessTable);
    }
    catch (Exception ex)
    {
        throw ex;
    }
    finally
    {
        if(destConn.State != ConnectionState.Closed)
            destConn.Close();
    }
}

这当然可以更有效，但我写它是为了快速转换。此外，由于这是复制和粘贴的，您可能需要对其进行调整。希望对您有所帮助。