Read

Jump to the Code block for a combined complete example.

Setup

The following examples will use the setup and record below to illustrate single record data retreival from an Aerospike database.

const Aerospike = require('aerospike');

// Define host configuration
let config = {hosts: '127.0.0.1:3000'};

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

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
let 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.

;(async () => {
    // Establishes a connection to the server
    let client = await Aerospike.connect(config);

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

    // Do something
    console.info("Exists: %o", exists);

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

Record metadata only

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

;(async () => {
    // Establishes a connection to the server
    let client = await Aerospike.connect(config);

    // Get record metadata
    let record = await client.select(key, [null]);

    // Do something
    console.info(record);

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

Whole record

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

;(async () => {
    // Establishes a connection to the server
    let client = await Aerospike.connect(config);

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

    // Do something
    console.info("Record: %o", record.bins);

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

Specific bins

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

;(async () => {
    // Establishes a connection to the server
    let client = await Aerospike.connect(config);

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

    // Do something
    console.info("Record: %o", record.bins);

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

Code block

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

const Aerospike = require('aerospike');

// Define host configuration
let config = {hosts: '127.0.0.1:3000'};

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

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

;(async () => {
    // Establishes a connection to the server
    let client = await Aerospike.connect(config);

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

    // Do something
    console.info("Record: %o", record.bins);

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