NoSQL (a) Why choose NoSQL?

"NoSQL essence" Reading notes, reproduced please indicate the source "Jiq Technical Blog"

The relational database has become a part of the computer culture because of its many advantages:

2 get persisted data

Data can be persisted to disk, and it is easy to access one of the small pieces of data.

2 concurrency

The relational database has the concept of "transaction", which effectively guarantees the consistency of multiple programs accessing the same data, and the acid (atomicity, consistency, isolation, persistence) characteristics of the transaction. I believe everyone is familiar with the heart.

2 Integrated

Different development teams, different platforms, different language applications can share the same data

2 The standard relational model

This is facilitated by the provision of a near-standard, unified relational model

But two reasons make relational databases seem inadequate:

? Impedance detuning

The data structure in memory is far from the relational model, which is called "impedance detuning (impedance mismatch)". Memory structures such as nested records, lists, and so on, need to be converted to "relational" and "tuple" before they can be stored.

? A swarm of swarms

With the rapid increase of network scale, the hardware computing resources "horizontal expansion" has become inevitable, cluster has become a trend, but the relational database is not designed for the cluster, or the use of "shared disk subsystem" to support the cluster file system (disk will become a bottleneck), or logically to the database shard, This allows the load to be distributed across multiple servers, but the application must control all shards, and transactions, consistency, and so on, cannot span shards.

Thus, NoSQL was born.

2 born for a cluster

NoSQL is basically thought of as a cluster (a small number of databases are not), when the amount of data to be processed is large, or grows at a faster rate, and requires high data access efficiency, consider nosql.

2 Impedance detuning

Remember that dealing with "big data" on a cluster is not the only reason for NoSQL, and impedance detuning is another key factor in NoSQL databases where there is no concept of "patterns" in traditional relational databases, and you can add fields without having to define a data storage model beforehand. Ideal for working with irregular data and custom fields, consider NoSQL when you want to improve application development efficiency in a more user-friendly way of interacting with your data.

NoSQL (a) Why choose NoSQL?