CRUD Operations in ArangoDB: A Practical Guide

CRUD (Create, Read, Update, Delete) operations are fundamental to any database system. In ArangoDB, these operations can be performed using AQL or through the ArangoDB Web Interface. In this post, we will explore each operation in detail, providing practical examples to illustrate how they work.

Creating Documents

The Create operation involves adding new documents to a collection. In ArangoDB, you can use the save method or AQL to insert documents.

Example 1: Using AQL to Create a Document

• To add a new user to the users collection:

aql
INSERT { "name": "Alice", "email": "alice@example.com", "age": 30 } INTO users

 

This command creates a new document in the users collection.

Example 2: Using the Web Interface

• Navigate to your users collection in ArangoDB Studio.
• Click the “Insert Document” button.
•  Enter the following JSON:

json
{
  "name": "Bob",
  "email": "bob@example.com",
  "age": 25
}

• Click “Save” to create the document.

Reading Documents

Reading documents involves querying the database to retrieve data. This can be done using simple AQL queries or by browsing through the Web Interface.

Example 1: Simple AQL Query
To retrieve all documents from the users collection:

aql
FOR user IN users
  RETURN user
 

Example 2: Retrieve a Specific Document by Key
To get a document with a specific key:

aql
FOR user IN users
  FILTER user._key == "user1"
  RETURN user

Updating Documents

The Update operation allows you to modify existing documents. In ArangoDB, you can use the UPDATE command in AQL.

Example 1: Update Using AQL
To update the email of a specific user:

aql
UPDATE "user1" WITH { "email": "alice.new@example.com" } IN users
 

This command updates the email address of the user with the key user1.

Example 2: Update Multiple Fields
You can also update multiple fields at once:

aql
UPDATE "user1" WITH { "age": 31, "city": "New York" } IN users

Deleting Documents

The Delete operation removes documents from the database. You can delete documents using AQL or the Web Interface.

Example 1: Delete Using AQL
To delete a specific user:

aql
REMOVE "user1" IN users

Example 2: Delete Multiple Documents
To delete all users older than 30:

aql
FOR user IN users
  FILTER user.age > 30
  REMOVE user IN users

Using Transactions

ArangoDB supports transactions, allowing you to perform multiple operations as a single unit of work. This ensures that either all operations succeed or none do, maintaining data integrity.

Example: Transactional Update
To update multiple user records in a single transaction:

javascript
db._executeTransaction({
  collections: {
    write: ["users"]
  },
  action: function() {
    db.users.update("user1", { "age": 31 });
    db.users.update("user2", { "age": 28 });
  }
});

Conclusion

CRUD operations are essential for managing data in ArangoDB. This post covered how to create, read, update, and delete documents using both AQL and the ArangoDB Web Interface. In the next post, we will delve into data modeling best practices, exploring how to design collections and relationships effectively in ArangoDB.