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Building Database Applications in Elixir with Ecto

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Part I: Ecto Fundamentals

Overview of Part I

Get Started with Repo

Ecto and Elixir

Characteristics of Ecto

Set Up the Sample Application

Running the Examples

Data Model of the Sample Application

The Repository Pattern

The Repo Module

Put Our Repo to Work

Get Values Back

Execute Queries

Customize Your Repo

Exercise: Customize Your Repo Module

Solution: Customize Your Repo Module

Quiz: Get Started with Repo

Query Your Database

Query Basics Refine Our Results with the Where Expression Protect Against SQL Injection Dynamic Values and Their Types Query Bindings Insert Raw SQL Combine Results with union and union_all Options Order and Group Work With Joins Why Use the Composing Queries Named Bindings Compose Queries with Functions Combine Queries with or_where Other Ways to Use Queries Exercise: Create Queries in Ecto Solution: Create Queries in Ecto Quiz: Query Your Database

Connect Tables to Elixir Structs with Schemas

Create Schemas How to Write Queries with Schemas Insert with Schemas Delete with Schemas Add Associations to Schemas Many-to-Many Associations Work with Associations in Queries Optimize Associations With Embedded Schemas Delete Records With Associations Use Schemas to Seed a Database Exercise: Create Schemas in Ecto Solution: Create Schemas in Ecto Quiz: Connect Tables to Elixir Structs with Schema

Make Changes with Changesets

Cast and Filter Validate Your Data Work with Constraints Capture Errors Use Changesets Without Schemas Work with Associations Associations Using Internal Data Associations Using External Data Update Records with Associations Best Practices for Associations Exercise: Create Changesets in Ecto Solution: Create Changesets in Ecto Quiz: Make Changes with Changesets

Make Multiple Changes with Transactions and the Multi Module

Run Transactions with Functions Force a Rollback Within a Transaction Execute Non-Database Operations Within a Transaction Drawbacks of Using Functions Run Transactions and Capturing Errors with Ecto.Multi Optimize Multi with Changesets Execute Non-Database Operations with Multi Exercise: Work with Transactions and the Multi Module Solution: Work with Transactions and the Multi Module Quiz: Make Multiple Changes

Make Changes to the Database

What are Migrations?Your First Migration Run Migrations Add Indexes Change Data and Table Structure Simultaneously Specify Up and Down Operations Change Default Behaviors Change Timestamps Run Migrations Outside of a Transaction Exercise: Create Migrations Solution: Create Migrations Quiz: Make Changes to your Database

Part II: Ecto Applied

Overview of Part II

Add Ecto to an Elixir Application Without Phoenix

Ecto in Elixir Applications: An Introduction Create a New Project Create Your Repo Module Add Ecto to the Supervision Tree Use Multiple Ecto Repos Start Your App Quiz: Add Ecto to an App without Phoenix

Work with Changesets and Phoenix Forms

Generate a Form for a Single Schema Display Changeset Errors Create a Form with an Association Create a Form with Multiple Associations Quiz: Work with Changesets and Phoenix Forms

Test with Sandboxes

Set Up an Async Test Change the Ownership Mode Safely Share Connections with Allowances Quiz: Test with Sandboxes

Create and Use Custom Types

Building on Top of Ecto’s Types Adding Custom Types Without the Built-In Types Quiz: Creating and Using Custom Types

Inserting and Updating with Upserts

Perform Upserts Without Schemas Perform Upserts with Schemas Exercise: Use Ecto's Upsert Feature Solution: Use Ecto's Upsert Feature Quiz: Insert and Update with Upserts

Optimizeing Your Application Design

Separate the Pure Code from the Impure Code Work with Context Work with Umbrella Applications Quiz: Optimize Your Application Design

Work with Embedded Schemas

Create Embedded Schemas Make Changes Choose Between Embedded Schemas and Associations Quiz: Work with Embedded Schemas

Creating Polymorphic Associations

Polymorphism in Other Frameworks Approach #1: Multiple Foreign Keys Approach #2: Use an Abstract Schema Approach #3: Use many_to_many Quiz: Creating Polymorphic Associations

Optimize IEx for Ecto

Add Imports and Aliases Add Helper Functions Quiz: Optimize IEx for Ecto

Use Schemas Without Tables

Schemas and Tables Create Table-less Schemas Save the Table-less Structs Quiz: Use Schemas Without Tables

Tune for Performance

Optimization Execute Bulk Operations Fetch Large Datasets With Streams Quiz: Tune for Performance

Conclusion

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Get Values Back

Get Values Back

Learn about the values returned by queries in Ecto.

Return value of queries

In each of the examples we’ve seen so far, Ecto returns a tuple. This is the standard return value for the *_all functions.

The first item in the tuple is the number of records affected by the operation.
The second

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