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tapingo-django-orm
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- 3. Ana Trakhtman Senior FullStack ana@tapingo.com (972) 526-204-634 Proprietary and Confidential
- 4. What we willtalk about 1) What is ORM? 2) Django Models 3) Querying in Django 4) Advanced querying in Django 5) Working with real production data and keeping it safe
- 5. So lets getstarted. Proprietary and Confidential
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- 7. 1. code librarythat automates the transfer of data stored in relational databases tables into objects that are more commonly used in application code high-level abstraction upon a relational database write Python code instead of SQL to create, read, update and delete data and schemas in database Object-relational mapper
- 8. How ORM lookslike in Django
- 9. Django Models 1. Amodel is the single, definitive source of information about your data 2. maps to a single database table 3. Python class that subclasses django.db.models.Model. 4. Each attribute of the model represents a database field 5. Django gives you an automatically-generated database-access API
- 10. Let’s take alook at how a real model looks like
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- 12. Querying in Django 1.a model class represents a database table 2. an instance of that class represents a particular record in the database table 3. QuerySet represents one or more record based on the lookup
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- 14. Behind the scenes •SELECT `orders_order`.`id`, `orders_order`.`is_mocked`, `orders_order`.`short_id`, `orders_order`.`owner_id`, `orders_order`.`tender_id`, `orders_order`.`referral_order_id`, `orders_order`.`shop_id`, `orders_order`.`order_type_id`, `orders_order`.`paytool_id`, `orders_order`.`creation_time`, AsText(`orders_order`.`location_owner`), `orders_order`.`is_tip_available`, `orders_order`.`suggested_tip_amount`, `orders_order`.`suggested_tip_percent`, `orders_order`.`suggested_tip_type`, `orders_order`.`has_suggestion`, `orders_order`.`clicked_suggestion`, `orders_order`.`suggestion_number`, `orders_order`.`tender_style`, `orders_order`.`is_first_for_user_global`, `orders_order`.`is_first_for_user_shop`, `orders_order`.`tapingo_credit`, `orders_order`.`merchant_credit`, `orders_order`.`balance_before`, `orders_order`.`suggestion_id`, `orders_order`.`is_scheduled`, `orders_order`.`estimated_print_time`, `orders_order`.`merchant_target_time`, `orders_order`.`organization_id`, `orders_order`.`is_on_campus`, `orders_order`.`device_id`, `orders_order`.`owner_organization_id`, `orders_order`.`is_shop_in_test_mode`, `orders_order`.`cancel_date`, `orders_order`.`is_valid_for_reporting`, `orders_order`.`is_valid_for_billing`, `orders_order`.`not_valid_for_billing_reason`, `orders_order`.`is_valid_for_execution`, `orders_order`.`is_selling_order`, `orders_order`.`user_response_time`, `orders_order`.`user_reported_ta`, `orders_order`.`no_tax_on_service_fee`, `orders_order`.`is_picked_up_by_user`, `orders_order`.`reco_on_menu`, `orders_order`.`current_equivalence`, `orders_order`.`is_odd` FROM `orders_order` WHERE `orders_order`.`id` = 1234
- 15. Get multiple instances Actually,I want only completed orders and only from a certain shop
- 16. What happened behindscenes • SELECT COUNT('*') AS `__count` FROM `orders_order` INNER JOIN `entities_profileentity` ON ( `orders_order`.`owner_id` = `entities_profileentity`.`entity_ptr_id` ) WHERE `entities_profileentity`.`email` = ‘ana@tapingo.com' • SELECT COUNT('*') AS `__count` FROM `orders_order` INNER JOIN `entities_profileentity` ON ( `orders_order`.`owner_id` = `entities_profileentity`.`entity_ptr_id` ) WHERE (`entities_profileentity`.`email` = 'ana@tapingo.com' AND `orders_order`.`state` = 'COMPLETED' AND `orders_order`.`shop_id` = 14474)
- 17. What if Iwant NOT? SELECT COUNT('*') AS `__count` FROM `orders_order` INNER JOIN `entities_profileentity` ON ( `orders_order`.`owner_id` = `entities_profileentity`.`entity_ptr_id` ) WHERE (`entities_profileentity`.`email` = 'ana@tapingo.com' AND NOT (`orders_order`.`state` = 'COMPLETED' AND `orders_order`.`shop_id` = 14474))
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- 19. Behind the scenes •SELECT `orders_order`.`id`, …, T5.`id`, T5.`name`, T5.`profile_photo_id`, T5.`last_update`, T5.`create_time`, `entities_profileentity`.`entity_ptr_id`, `entities_profileentity`.`user_id`, `entities_profileentity`.`last_name`, `entities_profileentity`.`email`, `entities_profileentity`.`birthdate`, `entities_profileentity`.`phone_number`, `entities_profileentity`.`business_day`, `entities_profileentity`.`trial_notified`, `entities_profileentity`.`is_waiter` FROM `orders_order` INNER JOIN `entities_profileentity` ON ( `orders_order`.`owner_id` = `entities_profileentity`.`entity_ptr_id` ) INNER JOIN `entities_shopentity` ON ( `orders_order`.`shop_id` = `entities_shopentity`.`entity_ptr_id` ) INNER JOIN `entities_entity` ON ( `entities_shopentity`.`entity_ptr_id` = `entities_entity`.`id` ) INNER JOIN `entities_entity` T5 ON ( `entities_profileentity`.`entity_ptr_id` = T5.`id` ) WHERE ((`entities_profileentity`.`email` = 'ana@tapingo.com' OR `entities_profileentity`.`email` = 'nadav@tapingo.com') AND `entities_entity`.`name` LIKE '%gables%' AND `orders_order`.`state` = 'COMPLETED') ORDER BY `orders_order`.`execution_time` DESC LIMIT 1
- 20. What else ispossible? 1. values/values_list - retrieve a sub set of fields 2. distinct - get only distinct instances based on specific field 3. reverse - reverse the order in which a queryset’s elements are returned 4. dates - Returns a QuerySet that evaluates to a list of datetime.date objects representing all available dates of a particular kind within the contents of the QuerySet
- 21. Advanced Querying inDjango
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- 23. Behind the scenes SELECT`entities_entity`.`id`, `entities_entity`.`name`, `entities_shopentity`.`what_now_html_takeaway_id`, `entities_shopentity`.`meal_hack`, `entities_shopentity`.`delivery_hack`, `entities_shopentity`.`dats`, `entities_shopentity`.`mark_new_until`, `entities_shopentity`.`mark_new_service_type`, `entities_shopentity`.`launch_date`, `entities_shopentity`.`target_orders`, `entities_shopentity`.`odd_pos_id`, `entities_shopentity`.`for_waiters`, `entities_shopentity`.`is_partner`, `entities_shopentity`.`is_supports_delivery`, `entities_shopentity`.`responsibilities`, COUNT(`orders_order`.`id`) AS `num_orders` FROM `entities_shopentity` LEFT OUTER JOIN `orders_order` ON ( `entities_shopentity`.`entity_ptr_id` = `orders_order`.`shop_id` ) INNER JOIN `entities_entity` ON ( `entities_shopentity`.`entity_ptr_id` = `entities_entity`.`id` ) WHERE NOT (`entities_shopentity`.`is_deleted` = 1) GROUP BY `entities_shopentity`.`entity_ptr_id` ORDER BY `num_orders` ASC LIMIT 1
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- 25. Behind the scenes SELECTAVG(`num_shops`) FROM (SELECT `billi_organization`.`id` AS Col1, COUNT(`entities_shopentity`.`entity_ptr_id`) AS `num_shops` FROM `billi_organization` LEFT OUTER JOIN `entities_shopentity` ON ( `billi_organization`.`id` = `entities_shopentity`.`organization_id` ) GROUP BY `billi_organization`.`id` ORDER BY NULL) subquery SELECT MAX(`num_shops`) FROM (SELECT `billi_organization`.`id` AS Col1, COUNT(`entities_shopentity`.`entity_ptr_id`) AS `num_shops` FROM `billi_organization` LEFT OUTER JOIN `entities_shopentity` ON ( `billi_organization`.`id` = `entities_shopentity`.`organization_id` ) GROUP BY `billi_organization`.`id` ORDER BY NULL) subquery
- 26. Running Raw SQL 1.Run your exact SQL 2. Maps to the model in use
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- 28. Gains 1. See realdata 2. See data in near real-time 3. Be pro-active and relevant
- 29. Risks 1. Data analytics= heavy queries 2. Locking time sensitive tables 3. Overloading the DB, impacting overall system performance
- 30. Solution - useread replica
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Editor's Notes
- #3 Introduce yourself and talk about why you are so excited to be part of the Tapingo team – a team that’s solving one of the most fundamental problems today: the way we buy things. Go around the room and talk about each person’s hopes and issues.
- #7 Present this as a “we all know” not as “we’re telling you something you don’t know.” People should be nodding in agreement here.
- #8 Like in any field, competition is a stone’s throw away. Or closer.
- #9 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #10 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #11 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #12 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #13 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #14 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #15 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #16 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #17 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #18 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #19 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #20 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #21 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #22 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #23 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #24 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #25 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #26 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #27 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #28 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #29 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #30 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #31 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.
- #32 Give examples of each. Spotify – no need to buy full albums, listen to exactly what you want. Uber – convenience is power. Amazon – no need to go to the store. UPS – even old-school companies leverage technology. You can track your package like never before.