Ruby: Can I write multi-line string with no concatenation?

Question

Is there a way to make this look a little better? conn.exec 'select attr1, attr2, attr3, attr4, attr5, attr6, attr7 ' + 'from table1, table2, table3, etc, etc, etc, etc, etc, ' + 'where etc etc etc etc etc etc etc etc etc etc etc etc etc'Like, is there a way to imply concatenation?

Answer 1

Hello there! You sure can, let me show you.

In your example, it looks like you're executing an SQL statement. Making multi-line SQL statements is actually something I have to do quite often. Ill use your SQL to construct the approach I would use when doing this.

Assuming this logic is wrapped in a class specifically designed to communicate with a database, your conn.exec lives inside a class and a method.

class MyModel

# ....

def query_database

conn.exec 'select attr1, attr2, attr3, attr4, attr5, attr6, attr7 ' +

'from table1, table2, table3, etc, etc, etc, etc, etc, ' +

'where etc etc etc etc etc etc etc etc etc etc etc etc etc;'

end

end

This works, as you probably already know. Now, to your question. You can actually omit the plus signs (+) all together. This also makes formatting with indentations easier. That would look something like this.

class MyModel

# ....

def query_database

conn.exec "

SELECT

attr1, attr2, attr3, attr4, attr5, attr6, attr7 

FROM

table1, table2, table3, etc, etc, etc, etc, etc,

WHERE

etc etc etc etc etc etc etc etc etc etc etc etc etc;"

end

end

One thing you'll notice right off the bat is our SQL statement now looks more like an SQL statement. This will aid in reading and debugging our SQL ( tomorrow and months from now ). Also, depending on what your stack looks like, this has the added benefit of being readable in any logs that show executed SQL. The previous way, with the plus signs, would all end up on the same line in your logs. When you break the lines like this, you get all the white space and new line characters.

IMPORTANT!

In your example, you didn't interpolate anything into your SQL statement. This is perfectly fine because it means you have complete control over what is executed. If you ever decide to create SQL based on user submitted values, I highly recommend you take a serious look at what SQL injection is and how to avoid it.

Hope this helps!