Django Data Seeding

This is a more flexible way of seeding data

1. Create required directories and files
$ mkdir testapp/management
$ mkdir testapp/management/commands
$ touch testapp/management/__init__.py
$ touch testapp/management/commands/__init__.py

2. Write code that populates the db
$ vi testapp/management/commands/populate_db.py
from django.core.management.base import BaseCommand
from testapp.models import Region
from django.db import connection

class Command(BaseCommand):
    args = ''
    help = 'Management script that populates the database with initial seed'

    def _truncate_region(self):
        cursor = connection.cursor()
        cursor.execute("TRUNCATE TABLE `testapp_region`")

    def _create_regions(self):
        regions = (
        ('REG001', [
                {"name": "vmk-4027","vlanId":4027,"usefor":["vsan","nfs"]},
                {"name": "vmk-4028","vlanId":4028,"usefor":["traffic"]},
                {"name": "vmk-102","vlanId":102,"usefor":["pub"]},
            ]),
        ('REG002', [
                {"name": "vmk-4029","vlanId":4029,"usefor":["vsan","nfs"]},
                {"name": "vmk-4030","vlanId":4030,"usefor":["traffic"]},
                {"name": "vmk-102","vlanId":103,"usefor":["pub"]},
            ]),
        )
        for item in regions:
            region = Region(name=item[0], vlans=item[1])
            region.save()

    def handle(self, *args, **options):
        self._truncate_region()
        self._create_regions()

3. Execute the program
$ python manage.py populate_db

Rails 4 Connect Existing Database

Once connect strings are specified in database.yml file, just add a model as follows:

class TestResult < ActiveRecord::Base
  self.table_name = "Test"
  self.primary_key = "testId"
end

Now, lets check from the console

$ rails c
Loading development environment (Rails 4.0.2)
2.0.0p353 :002 > TestResult.column_names
 => ["testId", "analysis", "archive", "baseline", "description", "engineer", "name", "project", "reference", "retention", "link", "errors"] 

Sqlite Cheat Sheet

This is from command line shell for sqlite.

1. Open sqlite database

$ sqlite3 db/development.sqlite3

2. List down tables

sqlite> .tables

3. Look at the schema

sqlite> .schema

4. Exit

sqlite> .exit

MySQL Cheat Sheet

1. Connect to MySQL server in localhost

>mysql -u username -p password [databasename]

2. Executing SQL Statements from a Text File

mysql> source c:\filename.sql

3. Migrate database

# everything
$ mysqldump -u [user] -p --opt mydb > mydb.sql

# To export to file (data only)
mysqldump -u [user] -p --no-create-info mydb > mydb.sql

# To export to file (structure only)
mysqldump -u [user] -p --no-data mydb > mydb.sql

# To import to database
mysql -u [user] -p mydb < mydb.sql