Read

Jump to the Code block for a combined complete example.

Description

Demonstrates single record reads in an Aerospike database.

Setup

Boilerplate

The following examples leverage the following boilerplate to initialize the Aerospike module and connect to a server before reading a record.

const Aerospike = await import("aerospike");

// Set hosts to your server's address and port
const config = { hosts: "YOUR_HOST_ADDRESS:YOUR_PORT" };

// Creates a key with the namespace "sandbox", set "ufodata", and user key 5001
const key = new Aerospike.Key("sandbox", "ufodata", 5001);

// Establishes a connection to the server
const client = await Aerospike.connect(config);

The record structure:

+------+----------+----------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------------------------------------------------------+
| PK   | occurred | reported | posted   | report                                                                                                                                                                                                                 | location                                                   |
+------+----------+----------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------------------------------------------------------+
| 5001 | 20220531 | 20220601 | 20220601 | MAP('{"shape":["circle", "flash", "disc"], "summary":"Large flying disc flashed in the sky above the student union. Craziest thing I've ever seen!", "city":"Ann Arbor", "state":"Michigan", "duration":"5 minutes"}') | GeoJSON('{"type":"Point","coordinates":[42.2808,83.743]}') |
+------+----------+----------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------------------------------------------------------+

Policies

Instead of using the default read policies, we can set them on a per command basis.

The following example creates a new read policy and sets the socket timeout for the command.

// Create a new read policy
const readPolicy = new Aerospike.ReadPolicy({
  socketTimeout: 300,
});

Read a record

Record exists

Checking record existence is faster than getting the record because it only needs to look at the primary index.

// Returns true if exists, false if not
const exists = await client.exists(key, readPolicy);

Record metadata only

Read record metadata (generation and expiration information) without reading the bins for a specified key.

// Returns a record with metadata if records with metadata exists.
// Returns empty record if non-existent
const record = await client.existsWithMetadata(key, readPolicy);

Whole record

Read the record metadata and all bins for a specified key.

// Get whole record
const record = await client.get(key, readPolicy);

Specific bins

Read the record metadata and the report and location bins from the record.

// Get bins 'report' and 'location'
const record = await client.select(key, ["report", "location"], readPolicy);

Code block

Expand this section for a single code block to read a record

const Aerospike = await import("aerospike");

// Set hosts to your server's address and port
const config = { hosts: "YOUR_HOST_ADDRESS:YOUR_PORT" };

// Creates a key with the namespace "sandbox", set "ufodata", and user key 5001
const key = new Aerospike.Key("sandbox", "ufodata", 5001);

// Establishes a connection to the server
const client = await Aerospike.connect(config);

// Create a new read policy
const readPolicy = new Aerospike.ReadPolicy({
  socketTimeout: 300,
});

// Get bins 'report' and 'location'
const record = await client.select(key, ["report", "location"], readPolicy);

console.info("Record: %o", record);

// Close the connection to the server
await client.close();