I am making an application with Rails 5 rc1. Rails 5 support mysql 5.7 json datatype.
add_column :organizations, :external, :json
Suppose the value in this column is as follows:
+---------------------------+
| external |
+---------------------------+
| {"id": 10, "type": "mos"} |
+---------------------------+
To search a particular "id" and "type" in external column, I use the following query in mysql:
select external from organizations where JSON_CONTAINS(external,'{"id": 10, "type": "mos"}') ;
Now, I want to know, how to make the same query using rails. The following doesn't work:
Organization.where("JSON_CONTAINS(external,'{"id": 10, "type": "mos"}')")
Note: I cannot remove quotes around the json text as it is part of the query.
您仍然可以利用ActiveRecord的where方法和绑定变量,而无需使用find_by_sql。
Organization.where("external->'$.id' = :id and external->'$.type' = :type", id: 10, type: "mos")
With MYSQL you can use JSON_EXTRACT
to pull values from a JSON object stored in a field. In your case, try using...
Organization.where("JSON_EXTRACT(external, '$.id') = 10 AND JSON_EXTRACT(external, '$.type') = 'mos'")
and just for kicks, in pseudo code...
<Class>.where("JSON_EXTRACT(<column_header>, '$.<object key>') <comparison operator> <object value>")
This should get the job done, although there may be a prettier way to write it :)
I did not find any solution through activerecord as of now. An alternative way to query is as follows:
type = "mos"
id = 10
organization = Organization.find_by_sql(["select * from organizations where JSON_CONTAINS(external_ref ,'{\"id\": ?, \"type\": \"#{ActiveRecord::Base::sanitize(type).remove("'")}\"}')", id]).first
Once there is a solution with activerecord query interface, I will update.
Like this:
id_field = '$."id"'
type_field = '$."type"'
Organization.where("JSON_UNQUOTE(json_extract(external, '#{id_field}')) = ? AND JSON_UNQUOTE(json_extract(external, '#{type_field}')) = ?", 10, "mos")
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