Help with calculation

rubyonrails-talk
1

I need some help with a calculation in a survey that I run.

I have one table with words, characteristics, such as "careful, dominant, positive" etc.

People are then to select the words they think belong to a visual detail, such as a square, circle, symmetry, etc. They can select 1-3 words.

These are then stored in one string field, as a string with space between each word, in the table used for answers. So each visual detail gets its own row with this "word field".

What is the best way to count how many that have selected one of the words for a particular visual detail, e.g how many have selected "hard" for a square?

I could collect the words in one find and then use count for each, but that will be many searches, so I figured I could do one search only in the answers table, and then loop through it and check how often the word is selected. But I'm not sure how to do that. I'm thinking of some functions in Array that I could use, or..?

Hopefully you understand the setup and my need. Any ideas?

2

The information is a bit vague, so I can't see the table names, but something like:

Model.count(:conditions => ["answer LIKE %?%", searched_word])

Add more conditions to select answers for squares only

Model.count(:conditions => ["answer LIKE %?% AND type='square'", searched_word]) (however this type information is stored)

Depending on the actual structure of your models/database, additional includes may be necessary or you may have to fall back on plain SQL.

In any case I would try to keep it in SQL for performance reasons, not let Ruby array functions count through lots of records.

3

I need some help with a calculation in a survey that I run.

I have one table with words, characteristics, such as "careful, dominant, positive" etc.

People are then to select the words they think belong to a visual detail, such as a square, circle, symmetry, etc. They can select 1-3 words.

These are then stored in one string field, as a string with space between each word, in the table used for answers. So each visual
detail gets its own row with this "word field".

What is the best way to count how many that have selected one of the words for a particular visual detail, e.g how many have selected
"hard" for a square?

Sounds to me like it would be easier for answer to has +many :visual_details (:through some appropriate join model) and
similarly in the other direction. You might end up with it being as easy as
some_visual_detail.words.count (though i suspect you'd end up needing
nested has many through for that level of conciseness (and that's not
supported yet)

Fred

4

Thorsten Mueller wrote:

The information is a bit vague, so I can't see the table names, but something like:

Model.count(:conditions => ["answer LIKE %?%", searched_word])

Add more conditions to select answers for squares only

Model.count(:conditions => ["answer LIKE %?% AND type='square'", searched_word]) (however this type information is stored)

Depending on the actual structure of your models/database, additional includes may be necessary or you may have to fall back on plain SQL.

In any case I would try to keep it in SQL for performance reasons, not let Ruby array functions count through lots of records.

Sorry for the vague info.

I thought of this. But isn't that a burden on the server searching for each word of, let's say 30, on several thousand answer? Or does it go fast enough?