CouchDB Notes

CouchDB is a database that completely embraces the web. Store your data with JSON documents. Access your documents with your web browser, via HTTP. Query, combine, and transform your documents with JavaScript.

Eventual Consistency (opens new window)

• Consistency: All database clients see the same data, even with concurrent updates.
• Availability: All database clients are able to access some version of the data.
• Partition tolerance: The database can be split over multiple servers.

Conflict resources

CouchDB uses an "optimistic concurrency" model. In the simplest terms, this just means that you send a document version along with your update, and CouchDB rejects the change if the current document version doesn't match what you've sent.

Question (opens new window)

Useful API

Database

• HEAD /{db} - get info
• PUT /{db} - create database
• DELETE /{db} - delete database
• GET /_all_dbs - find databases
• POST /{db}/index - create index
• PUT /{db}/_revs_limit - Sets the max no of document revisions that will be tracked by CouchDB
• GET /{db}/_changes - polling changes

Document

• HEAD /{db}/${docid} - get info
• GET /{db}/${docid} - get document
• PUT /{db}/${docid} - create / update document
• DELETE /{db}/${docid} - delete document
• POST /{db}/_bulk_docs - upsert / delete documents
• POST /{db}/_find - Find documents using a declarative JSON querying syntax
• GET /{db}/_all_docs - executes the built-in _all_docs view

Basic usage from axios

const authToken = Buffer.from(`${configs.couchUser}:${configs.couchPass}`).toString("base64");

const axiosClient = axios.create({
    baseURL: `${configs.couchHost}:${configs.couchPort}`,
    headers: {
    Authorization: `Basic ${authToken}`,
    },
});

Create database & create index & set revision

const databaseName = `test_db`;

await axiosClient.put(`/${databaseName}`, {});

await axiosClient.post(`/${databaseName}/_index`, {
  index: {
    fields: ["createdAt"],
  },
});

await axiosClient.put(`/${databaseName}/_revs_limit`, `20`);