Django ORM SELECT with joining

Question

Models in django:

class Key(models.Model): id = models.AutoField(primary_key=True, blank=True) name = models.CharField(max_length=50) class Record(models.Model): id = models.AutoField(primary_key=True, blank=True) project_id = models.IntegerField() name = models.CharField(max_length=50) class Value(models.Model): id = models.AutoField(primary_key=True, blank=True) record = models.ForeignKey(Record) key = models.ForeignKey(Key) value = models.CharField(max_length=255) 

I need to select the following data from the database:

 NAME (from record) and fields related with this record [NAME (from key), VALUE (from value)] [NAME (from key), VALUE (from value)] [...] 

Is it possible to use django ORM for this choice? (for example, in SQL select it looks like this)

 SELECT `keeper_record`.`id` AS `record_id`, `keeper_record`.`name` AS `name`, `keeper_record`.`desc` AS `desc`, `keeper_key`.`name` AS `key_name`, `keeper_key`.`desc` AS `key_desc`, `keeper_value`.`value` AS `value_value` FROM `keeper_record` JOIN `keeper_value` ON `keeper_record`.`id` = `keeper_value`.`record_id` JOIN `keeper_key` ON `keeper_key`.`id` = `keeper_value`.`key_id` WHERE record_id = id 

Answer 1

Next, values ​​related to a specific record identifier are selected. Then you can execute foreign keys to get the corresponding entry and key. Using select_related minimizes database lookups.

 # Select all values related to a record in your view record = Record.objects.get(pk=record_id) values = Value.objects.filter(record=record).select_related() # In your template {% for value in values %} {{ value.record.name }} - {{ value.key.name }} - {{ value.value }} {% endfor %} 

Select more than one entry

In your sql you had WHERE record_id = 1 , so I showed how to get all the values ​​for a particular record. You can also select values ​​for more than one record in a single query.

 # filter all records which belong to the project with `project_id=1` records = Record.objects.filter(project_id=1) # select all values that belong to these records values = Value.objects.filter(record__in=records).select_related().order_by('record') 

Answer 2

It should be relatively simple since you already have foreign keys connected to each other.

 Record.objects.select_related().filter(id = variable_that_stores_id) 

You can combine this with only to restrict the fields you want to return.