This example shows the best practice of using prepared statements in the Node.js DataStax Driver to write and read data from a Cassandra database.
Contributor(s): Dave Bechberger
Objectives
- Learn how to use prepared statements in Node.js
Project Layout
- app.js - The main application file, contains the example code for using prepared statements
How this Works
This example first creates a videos table in the examples keyspace.
Once this table is created the code runs an INSERT and SELECT CQL query using a prepared statement. To create a statement as a prepared statement in Node.js you use a command like:
client.execute(query, params, { prepare: true })
The critical part of that command is the third parameter { prepare: true }. Adding this parameter makes this a prepared statement. Prepared statements are beneficial for several reasons:
- Prepared statements are parsed and stored on the Cassandra nodes which increase the performance of subsequent queries by preparing them once and executing them many times with bound parameters
- Prepared statements allow for proper mapping of Javascript types to Cassandra types
Setup and Running
Prerequisites
- Node.Js version 8 ( download )
- A Cassandra, DDAC, DSE cluster or Apollo database ( docker is a nice option for local install - see docs )
Note This application defaults to connecting to a cluster on localhost with a local data center of dc1. If this is not the case then you will need to change the following in app.js:
const client = new cassandra.Client({ contactPoints: ['127.0.0.1'], localDataCenter: 'dc1' });
Running
To run this application use the following command:
node app.js
This will produce the following output:
Inserting Data Using a Prepared Statement Selecting Data Using a Prepared Statement Video Id: 1665ffe0-77eb-4047-8791-f043accda4dd, User Id: 98462781-327b-40dc-9036-91702afdeb77, Name: Test Movie, Description: Test Description
