MySqlBulkLoader with Column Mapping?

问题

I use SqlBulkCopy to do bulk inserts into a SQL Server database. I am now providing MySql support for my program and the nearest thing to SqlBulkCopy is MySqlBulkLoader. But in MySqlBulkLoader, I have to first convert my DataTable to a file because MySqlBulkLoader only works with files and not DataTable. And then I have to disable foreign key checks before the insert. I have done them both but now I am left with one more problem:

My destination table has an identity column (auto-increment and PK) and MySqlBulkLoader maps the first column in the source file to this column and therefore only the first record is inserted with wrong column mappings. Here is how I use the function if it helps:

using (var conn = new MySqlConnection(connectionString))
{
    var bl = new MySqlBulkLoader(conn);
    bl.TableName = tableName;
    bl.Timeout = 600;
    bl.FieldTerminator = ",";
    bl.LineTerminator = "\r\n";
    bl.FileName = tempFilePath;
    bl.NumberOfLinesToSkip = 1;
    numberOfInsertedRows = bl.Load();
}

And this is first few lines on my file:

CampaignRunId,RecipientId,IsControlGroup
27,"testrecipient_0",False
27,"testrecipient_1",False
27,"testrecipient_2",False
27,"testrecipient_3",False
27,"testrecipient_4",False
27,"testrecipient_5",False
27,"testrecipient_6",False
27,"testrecipient_7",False
27,"testrecipient_8",False
27,"testrecipient_9",False
27,"testrecipient_10",False
27,"testrecipient_11",False
27,"testrecipient_12",False
27,"testrecipient_13",False

Is there a way to provide column mapping for MySqlBulkLoader? I see that it has a Columns property but it is read-only.

There is a library written somewhere called MySqlBulkCopy but I ran into other problems using it and it does not come from an official source.

回答1:

I've recently been using MySqlBulkLoader also, and came across the need to use the Columns property in order to format a date that was pulled out of MSSQL into the right format to insert into MySQL. The columns property is readonly, but that just means you need to set the properties when you create the object, rather than afterwards.

First, change this block of code

using (var conn = new MySqlConnection(connectionString))
{
    var bl = new MySqlBulkLoader(conn);
    bl.TableName = tableName;
    bl.Timeout = 600;
    bl.FieldTerminator = ",";
    bl.LineTerminator = "\r\n";
    bl.FileName = tempFilePath;
    bl.NumberOfLinesToSkip = 1;
    numberOfInsertedRows = bl.Load();
}

to this:

using (var conn = new MySqlConnection(connectionString))
{
    var bl = new MySqlBulkLoader(conn)
    {
        TableName = tableName,
        Timeout = 600,
        FieldTerminator = ",",
        LineTerminator = "\r\n",
        FileName = tempFilePath,
        NumberOfLinesToSkip = 1
    };
    var numberOfInsertedRows = bl.Load();
}

Then, you can go ahead an use whatever value you want to for the Columns property, so your final code block may look something like this:

using (var conn = new MySqlConnection(connectionString))
{
    var bl = new MySqlBulkLoader(conn)
    {
        TableName = tableName,
        Timeout = 600,
        FieldTerminator = ",",
        LineTerminator = "\r\n",
        FileName = tempFilePath,
        NumberOfLinesToSkip = 1,
        Columns = { "CampaignRunId", "RecipientId", "IsControlGroup" }
    };
    var numberOfInsertedRows = bl.Load();
}

回答2:

Building on David Hartley's answer: if you don't know the column names a priori, you could just clear the list of column and add items to it afresh.

It'll be something like this:

bl.Columns.Clear(); foreach (string col in yourColumns) { bl.Columns.Add(col); }

来源：https://stackoverflow.com/questions/28691620/mysqlbulkloader-with-column-mapping

标签

mysql

bulkinsert

sqlbulkcopy