Introduction

Couchbase Server is a NoSQL document database for interactive web applications. It has a flexible data model, is easily scalable, provides consistent high performance and is “always-on,” meaning it can serve application data 24 hours, 7 days a week.

Important: A newer version of this software with updated documentation is available. Visit the Couchbase Developer Portal for more information.

Couchbase benefits

With Couchbase Server, JSON documents are used to represent application objects and the relationships between objects. This document model is flexible enough so that you can change application objects without having to migrate the database schema, or plan for significant application downtime. Even the same type of object in your application can have different data structures. For instance, you can initially represent a user name as a single document field. You can later structure a user document so that the first name and last name are separate fields in the JSON document without any downtime and without having to update all user documents in the system.

  • Flexible data model

    The other advantage in a flexible, document-based data model is that it is well suited to representing real world items and how you want to represent them. JSON documents support nested structures, as well as fields representing relationships between items which enable you to realistically represent objects in your application.

  • Easy scalability

    It is easy to scale your application with Couchbase Server, both within a cluster of servers and between clusters at different data centers. You can add instances of Couchbase Server to address increases in users and application data without any interruptions or changes in your application code. With a single click of a button, you can rapidly grow your cluster of Couchbase Servers to handle additional work and keep data evenly distributed.

    Couchbase Server provides automatic sharding of data and rebalancing at runtime; this lets you resize your server cluster on demand. Cross-data center replication enables you to move data closer to your users at other data centers.

  • Consistent high performance

    Couchbase Server is designed for massively concurrent data use and consistent high throughput. It provides consistent sub-millisecond response times which help ensure an enjoyable experience for users of your application. By providing consistent, high data throughput, Couchbase Server enables you to support more users with less servers. The server also automatically spreads workload across all servers to maintain consistent performance and reduce bottlenecks at any given server in a cluster.

  • "Always online"

    Couchbase Server provides consistent sub-millisecond response times which help ensure an enjoyable experience for users of your application. By providing consistent, high data throughput, Couchbase Server enables you to support more users with less servers. The server also automatically spreads workload across all servers to maintain consistent performance and reduce bottlenecks at any given server in a cluster.

    Features such as cross-data center replication, failover, and backup and restore help ensure availability of data during server or datacenter failure.

All of these features of Couchbase Server enable development of web applications where low-latency and high throughput are required by end users. Web applications can quickly access the right information within a Couchbase cluster and developers can rapidly scale up their web applications by adding servers.

Couchbase Server and NoSQL

NoSQL databases are characterized by their ability to store data without first requiring one to define a database schema. In Couchbase Server, you can store data as key-value pairs or JSON documents. Data does not need to confirm to a rigid, pre-defined schema from the perspective of the database management system. Due to this schema-less nature, Couchbase Server supports a scale out approach to growth, increasing data and I/O capacity by adding more servers to a cluster; and without any change to application software. In contrast, relational database management systems scale up by adding more capacity including CPU, memory and disk to accommodate growth.

Relational databases store information in relations which must be defined, or modified, before data can be stored. A relation is simply a table of rows, where each row in a given relation has a fixed set of columns. These columns are consistent across each row in a relation. Tables can be further connected through cross-table references. One table, could hold rows of all individual citizens residing in a town. Another table, could have rows consisting of parent, child and relationship fields. The first two fields could be references to rows in the citizens table while the third field describes the parental relationship between the persons in the first two fields such as father or mother.