Elasticity (data store)
Encyclopedia
The elasticity of a data store
relates to the flexibility of its data model
and clustering
capabilities. The greater the number of data model changes that can be tolerated, and the more easily the clustering can be managed, the more elastic the data store is considered to be.
data store. Usually, this is a difficult and delicate task to be done by an expert in a relational database system. Some NoSQL data stores, like Apache Cassandra, have an easy solution, and a node can be added/removed with a few changes in the properties and by adding specifying at least one seed.
s are most often very inelastic, as they have a predefined data model that can only be adapted through redesign. NoSQL data stores, however, do not have a fixed schema
. Each row can have a different number and even different type of columns. Concerning the data store, modifications in the schema are no problem. This makes this kind of data stores more elastic concerning the data model. The drawback is that the programmer has to take into account that the data model may change over time.
Data store
A data store is a data repository of a set of integrated objects. These objects are modeled using classes defined in database schemas. Data store includes not only data repositories like databases, it is a more general concept that includes also flat files that can store data.Some data stores do...
relates to the flexibility of its data model
Data model
A data model in software engineering is an abstract model, that documents and organizes the business data for communication between team members and is used as a plan for developing applications, specifically how data is stored and accessed....
and clustering
Clustering
Clustering can refer to the following:In demographics:* Clustering , the gathering of various populations based on factors such as ethnicity, economics or religion.In graph theory:...
capabilities. The greater the number of data model changes that can be tolerated, and the more easily the clustering can be managed, the more elastic the data store is considered to be.
Clustering elasticity
Clustering elasticity is the ease of adding or removing nodes from the distributedDistributed computing
Distributed computing is a field of computer science that studies distributed systems. A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal...
data store. Usually, this is a difficult and delicate task to be done by an expert in a relational database system. Some NoSQL data stores, like Apache Cassandra, have an easy solution, and a node can be added/removed with a few changes in the properties and by adding specifying at least one seed.
Data-modelling elasticity
Relational databaseRelational database
A relational database is a database that conforms to relational model theory. The software used in a relational database is called a relational database management system . Colloquial use of the term "relational database" may refer to the RDBMS software, or the relational database itself...
s are most often very inelastic, as they have a predefined data model that can only be adapted through redesign. NoSQL data stores, however, do not have a fixed schema
Schema
The word schema comes from the Greek word "σχήμα" , which means shape, or more generally, plan. The plural is "σχήματα"...
. Each row can have a different number and even different type of columns. Concerning the data store, modifications in the schema are no problem. This makes this kind of data stores more elastic concerning the data model. The drawback is that the programmer has to take into account that the data model may change over time.