SqlBulkCopy引发异常：无法将数据源中String类型的给定值转换为指定目标列的bigint类型

Question

I'm trying for the first time to use SqlBulkCopy . I have a table created this way:

IF NOT EXISTS(SELECT 1 FROM sys.tables 
              WHERE Name = N'DetectionLoggingTime' 
                AND Object_ID = Object_ID(N'dbo.DetectionLoggingTime'))
BEGIN
    PRINT N'Creating [dbo].[DetectionLoggingTime]...';

    CREATE TABLE [dbo].[DetectionLoggingTime]
    (
        [LogId]       INT PRIMARY KEY IDENTITY(1,1) NOT NULL,
        [ScreeningId] BIGINT        NOT NULL,
        [Message]     NVARCHAR(255) NOT NULL,
        [Time]        BIGINT        NULL
    );
END

I am trying to insert values in this way:

public async Task Handle(DetectionLoggingIntegrationEvent @event)
{
    var dt = new DataTable();
    dt.Columns.Add("ScreeningId");
    dt.Columns.Add("Message");
    dt.Columns.Add("Time");

    @event.OperationTimePairs.ForEach(pair => dt.Rows.Add(@event.ScreeningId, pair.Key, pair.Value));

    using (var sqlBulk = new SqlBulkCopy(_configProvider.MyConnectionString))
    {
        sqlBulk.DestinationTableName = "DetectionLoggingTime";
        sqlBulk.WriteToServer(dt);
    }
}

My feeling is that the insertion is trying to insert the LogId which I would like it to be incremental and automatically generated by SQL Server. What am I doing wrong?

Answer 1

Found the solution, explicit column mappings are required:

public async Task Handle(DetectionLoggingIntegrationEvent @event)
{
    var dt = new DataTable();
    dt.Columns.Add("ScreeningId", typeof(long));
    dt.Columns.Add("Message");
    dt.Columns.Add("Time", typeof(long));

    @event.OperationTimePairs.ForEach(pair => dt.Rows.Add(@event.ScreeningId, pair.Key, pair.Value));

    using (var sqlBulk = new SqlBulkCopy(_configProvider.FdbConnectionString))
    {
        var mapping = new SqlBulkCopyColumnMapping("ScreeningId", "ScreeningId");
        sqlBulk.ColumnMappings.Add(mapping);

        mapping = new SqlBulkCopyColumnMapping("Message", "Message");
        sqlBulk.ColumnMappings.Add(mapping);

        mapping = new SqlBulkCopyColumnMapping("Time", "Time");
        sqlBulk.ColumnMappings.Add(mapping);

        sqlBulk.DestinationTableName = "DetectionLoggingTime";
        sqlBulk.WriteToServer(dt);
    }
}

Answer 2

That issue is often caused before the column type in the DataTable are not explicit.

By example, setting the column type might fix that error:

var dt = new DataTable();
dt.Columns.Add("ScreeningId", typeof(long));
dt.Columns.Add("Message");
dt.Columns.Add("Time", typeof(long));

More documentation about this issue here: https://sqlbulkcopy-tutorial.net/type-a-cannot-be-converted-to-type-b