cannot retain id of first table in left join - mysql

Question

I am using sails waterline ORM and i have three tables in my model layer
1-s_class
attributes: {
c_title:{
type:'string',
required: true
},
sec:{
collection:'s_section',
via:"cls"
},
s_session:{
model:'s_session',
columnName:'session'
}
}
2-s_section
attributes: {
sec_title:{
type:'string'
},
sec_priority:{
type:'integer',
required: true
},
cls:{
collection:'s_class',
via:"sec"
}
}
3-s_form
attributes: {
studentName:{
type:'string'
},
s_class:{
columnName:'s_class',
model:'s_class'
},
s_section:{
columnName:'s_section',
model:'s_section'
}
}
i assigned both class and section to student which are saved in s_form table.when i write a query to get a student's record alongwith his class and section.something like this:
s_form.query("SELECT * FROM s_form LEFT OUTER JOIN s_class ON s_form.s_class=s_class.id LEFT OUTER JOIN s_section ON s_form.s_section=s_section.id",function(err,forms){
if(!err)
else{
res.json(forms);
}
});
it populates record of section and class but also affects auto increment primery key of s_form.actually this is because s_section and s_class also have default auto increment primery keys which after populating conflicts and in this case i got id of s_section.
i want to get id of s_form.is there any way to avoid this conflict and overriding of id without affecting default behavior of primery keys????
Note
s_form table contains custom columns means the columns mentioned above are static but it also contain columns which are created at runtime.that's why i can't use built in populate() query method nor i can specify column names like instead of select *.....

Answer 1

Based on your edited / updated post you I would query query to retrieve your column names prior to executing the query so that you can iterate over them and pass the table name as a prefix to each column name. This would allow you to avoid any conflicts.
You can use the following to get column names
SELECT *
FROM `INFORMATION_SCHEMA`.`COLUMNS`
WHERE `TABLE_SCHEMA`='yourdatabasename'
AND `TABLE_NAME`='yourtablename';
You can use this after your dynamic tables are created and save it in a variable so you don't have to keep doing it on every query.

Answer 2

Well, first you can have sails do this for you
s_form.find().populate('').populate('').exec(function(err,forms){/*....*/});
If you want to use query then you need to explicitly name your fields in order to avoid the conflict that will happen.
Instead of SELECT * FROM
You should specific each field so can rename the Id field to avoid these conflicts.
SELECT
s_class.c_title, s_class.id as classId,
s_section.sec_title,s_section.sec_priority,s_section.id as sectionId,
s_form.studentName,s_form.id as formId
FROM FROM s_form LEFT OUTER JOIN s_class ON s_form.s_class=s_class.id LEFT OUTER JOIN s_section ON s_form.s_section=s_section.id