codesnips

database

ruby 
class CreateComments < ActiveRecord::Migration[6.1]
  def change
    create_table :comments do |t|
      t.references :commentable, polymorphic: true, null: false
      t.references :author, null: false, foreign_key: { to_table: :users }
      t.text :body, null: false

Polymorphic associations for flexible relationships

rails activerecord database
by Alex Kumar 3 tabs
ini 
; PgBouncer configuration file

[databases]
; Database connection strings
mydb = host=localhost port=5432 dbname=mydb
analytics = host=replica.example.com port=5432 dbname=mydb

Connection pooling and configuration

database connection-pooling pgbouncer
by Maria Garcia 2 tabs
sql 
CREATE TABLE country (
    code       CHAR(2)      PRIMARY KEY,
    name       VARCHAR(128) NOT NULL,
    currency   CHAR(3)      NOT NULL,
    updated_at TIMESTAMPTZ  NOT NULL DEFAULT now()
);

Seeding Reference Data After a Flyway Migration with a Java Callback

flyway spring-boot migrations
by codesnips 3 tabs
python 
from django.db import transaction
from django.shortcuts import get_object_or_404
from django.http import JsonResponse
from .models import Product

Django select_for_update for database locking

django python database
by Priya Sharma 1 tab
ruby 
require 'activerecord-import'

class BulkImportPostsService
  BATCH_SIZE = 1000

  def initialize(csv_file_path)

Bulk operations with ActiveRecord import

rails performance activerecord
by Alex Kumar 1 tab
kotlin 
package com.example.myapp.data.local

import android.content.Context
import androidx.room.*
import androidx.sqlite.db.SupportSQLiteDatabase
import kotlinx.coroutines.CoroutineScope

Room database for local persistence

kotlin android room
by Alex Chen 2 tabs
sql 
-- Primary server configuration (postgresql.conf)
-- wal_level = replica
-- max_wal_senders = 10
-- wal_keep_size = 64MB
-- hot_standby = on

Database replication and high availability strategies

database replication high-availability
by Maria Garcia 2 tabs
ruby 
class AddLockVersionToPosts < ActiveRecord::Migration[6.1]
  def change
    add_column :posts, :lock_version, :integer, default: 0, null: false
  end
end

Optimistic locking for concurrent updates

rails database concurrency
by Alex Kumar 2 tabs
python 
from decimal import Decimal

from django.db import models
from django.db.models import F, ExpressionWrapper, DecimalField

Annotate Invoice Line Totals in a Django ListView Queryset

django orm queryset
by codesnips 3 tabs
go 
package feed

import "time"

type Post struct {
	ID        int64

Batch-Load Related Rows with a Single IN Query to Avoid N+1

go sql postgres
by codesnips 3 tabs
sql 
-- Migration naming convention: V{version}__{description}.sql
-- Example: V001__create_users_table.sql

-- Migration 1: Create initial schema
-- V001__create_users_table.sql
CREATE TABLE users (

Database schema migrations and versioning

database migrations schema-evolution
by Maria Garcia 2 tabs
yaml 
production:
  adapter: postgresql
  encoding: unicode
  pool: <%= ENV.fetch("RAILS_MAX_THREADS", 5) %>
  timeout: 5000
  checkout_timeout: 5

Database connection pooling configuration

rails database performance
by Alex Kumar 2 tabs