![]() Then we loop over the hash with the bindings and replace them with numbered variables of the form $ 1, $ 2, etc. It is clear that the binding in the query and hash must match. The execute method takes a query string and a hash with binding. New = SqlQuery.execute(sql, binding).first JSON.parse(json, symbolize_names: true) rescue jsonĪs you can see from the code, everything is as simple as the corner of the house. Result = ActiveRecord::_query(sql, 'SQL', bindings).map(& :symbolize_keys)Įnd end end # Convert JSON to hash if correct data # json string # return hash if json is correct or input data def self. execute (sql, bind = ")Įnd end # Execute query, convert to hash with symbol keys ![]() # Can use if not need get model object! class SqlQuery # Create sql query with hash bindings # sql SQL query # bind bindings data for query # executed SQL request data and return array with hashes def self. Why there are no named binders when working with native queries is a mystery to me, but the solution is to write my own little wrapper that can work very easily with named binders, which I did. But if the request is really complicated, then to drive it through the model and Active Record itself is a big loss in speed (slow) and performance (it is consuming server resources). But the question is, it is more or less acceptable if you want to perform a simple query. Here everything is more pleasant and clearer. Sql = 'SELECT id, name, desc FROM schema.news WHERE id=:id' Alternatively, you can use the find_by_sql method call for the model class: And this greatly complicates the reading and support of native queries. Bindings cannot be named but only numbered. The example above shows that the formation of binders occurs, to put it mildly, in one place, when we are trying to get news from the database at number 100. New = ActiveRecord::_query(sql, 'SQL', bindings).first Sql = 'SELECT id, name, desc FROM schema.news WHERE id=$1' The main method that allows you to execute your own SQL queries is exec_query: But there is a solution :) Tested and successfully implemented on a project with Rails API 5.2 + Ruby 2.6.0 + Postgres 11. But in Rails there is one unpleasant trifle, the functionality of executing native queries does not allow the use of named binding. Imagine that you need to make a very complex query for PostgreSQL in a native way (on pure SQL), where there must be a certain number of variables. It's no secret that working on large projects with complex logic, Active Record becomes not a helper, but a burden. We refrained from refactoring it to a gem/DSL, so the code examples read a little nicer.Hello friends. If you have any questions, feel free to reach out. ![]() Yet, the master branch combines them into more complete solution. Also note the heitor, tom and dmitry branches, which have different approaches to the same problem. Old records stay valid and usable if the default value of the schema changes, and querying inside the description is ok due to PostgreSQL power with JSONB fields.Ī complete version of this idea can be seen in this GitHub repo. With the schema definition and a little Rails magic, we also enable validations. We are now able to have a relational database delivering multiple records of the same table, each one with different set of attributes. Remember that with JSONB, we have indexes called GIN / GiST to help with performance. # description->sound = 'Pioneer' Vehicle. ![]() We want every new instance of vehicle to have its schema filled by a default value declared in the database table. Required fields are also being declared in the schema for later validations. This enables us to have a different set of attributes for each record of the table. The schema defines attributes, telling us their type and default value. It held a schema and a description keeping its characteristics. After we did some brainstorming and white board sessions, we decided to start with a Model called Vehicle. This was a joint effort between me, Tom Rothe and Dmitry Parshenko. That was easily solved with a JSON field, but we also wanted to support validations on this field – validations that are assigned to the model at the time of creation. We knew that the columns for one particular model would need to change over time. JSON dynamic attributes with Rails we are 3-in-1: a technologist, a trainer, an organizer. ![]()
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