引号内的Ruby代码注释

Question

I have a multi-line SQL command string in my Ruby script. I am adding some extra lines to the SQL command string, and want to supplement it with some in-line comments.

mysql.query("CREATE TABLE If NOT EXISTS #{table}(
    application varchar(255),
    eventType varchar(255),
    eventTs datetime,
    eventDayWeek int,
    newColumnHere int, #Hello, I would like to be a comment
    eventHourDay int,

    ....)")

How does one add code comments within a set of quotes?

Answer 1

MySQL does support comment syntax so your code should work as is. However, I would prefer to use a "heredoc":

mysql.query <<END
CREATE TABLE If NOT EXISTS #{table}(
    application varchar(255),
    eventType varchar(255),
    eventTs datetime,
    eventDayWeek int,
    newColumnHere int, #Hello, I would like to be a comment
    eventHourDay int,

    ....)
END

Answer 2

You could just break the string in two, or alternatively include an SQL comment.

For the first option:

"CREATE TABLE ...
newColumnHere int, " +
# comment in ruby here
"eventHourDay int, ...

Or the second option:

newColumnHere int,  -- SQL comments from double dash to end of line
eventHourDay int,