SqlCommand() ExecuteNonQuery() truncates command text.

Question

I'm building a custom db deployment utility, I need to read text files containing sql scripts and execute them against the database.

Pretty easy stuff, so far so good.

However I've encountered a snag, the contents of the file are read successfully and entirely, but once passed into the SqlCommand and then executed with SqlCommand.ExecuteNonQuery only part of the script is executed.

I fired up Profiler and confirmed that my code is not passing all of the script.

    private void ExecuteScript(string cmd, SqlConnection sqlConn, SqlTransaction trans)
    {

        SqlCommand sqlCmd = new SqlCommand(cmd, sqlConn, trans);
        sqlCmd.CommandType = CommandType.Text;
        sqlCmd.CommandTimeout = 9000000; // for testing
        sqlCmd.ExecuteNonQuery();

    }

    // I call it like this, readDMLScript contains 543 lines of T-SQL
    string readDMLScript = ReadFile(dmlFile);
    ExecuteScript(readDMLScript, sqlConn, trans);

Answer 1

Answer based on comments under the original post:

GO is a marker for Management Studio / osql / isql. It tells to send a batch of commands to SQL Server. In your utility, you should split the input data using GO as a delimiter and send each element individually (without the GO command)

Answer 2

Yep, everyone hits this snag the first time they start sending the contents of SQL script files to the database.

GO is not a T-SQL command. It's the end-of-batch marker recognised by all the Microsoft interactive SQL tools (Management Studio, isql, osql). In order to handle it, you will have to write your own "parser" to break out every block of text in the file between GO statements and feed them to the database as separate commands.

How you implement your parser is up to you. It can be simple - read in each line at a time, detect lines that consist of nothing but GO and whitespace. It can be more complex - tokenising all the statements and working out whether a GO is a genuine statement or a bit of text inside a string or multi-line comment.

Personally I went with the first option. It handles 99% of all SQL files you are ever likely to encounter with no fuss. If you want to go the whole hog and write a tokeniser, I'm sure lots of people have done one already, just Google for it.

Example:

using(var reader = new MySqlBatchReader(new StreamReader(dmlFile))) {
    string batch;
    while((batch = reader.ReadBatch()) != null) {
        var cmd = new SqlCommand(batch, conn, trans) { CommandType = CommandType.Text };
        cmd.ExecuteNonQuery();
    }
}

class MySqlBatchReader : IDisposable {
    private TextReader _reader;
    public MySqlBatchReader(TextReader reader) {
        _reader = reader;
    }
    // Return the next command batch in the file, or null if end-of-file reached.
    public string ReadBatch() {
        // TODO
    }
}