NoSQL database overview and comparison with SQL syntax (1)

NoSQL database overview and comparison with SQL syntax (1)

Abstr]

HBase is a highly reliable, high-performance, column-oriented, and Scalable Distributed Storage System. It is also one of the well-known NoSQL databases. The emergence of NoSQL databases is to solve the challenges posed by multiple data types in large-scale data sets, especially the difficulties of big data applications.

This article briefly introduces the definition, classification, features, and popular NoSQL database systems of NoSQL databases, and compares the NoSQL and SQL syntaxes, it provides a useful reference for learning NoSQL databases.

I. emergence of NoSQL

Relational Database systems have achieved great success in solving data storage, services, and handling problems over the years. Some large companies use relational databases to establish their own systems, such as online transaction processing systems and backend analysis application systems. The online transaction processing (OLTP) system is used to record transaction information in real time. The expectation for such systems is the ability to quickly return response information (generally within milliseconds ). The OLAP system is used to analyze and query stored data. OLAP is a category of business intelligence. data needs to be researched, processed, and analyzed to collect information and further drive business decision-making.

The internal design of relational databases is determined by relational algorithms. These systems need to pre-define a schema and the types of data to comply. SQL is the standard way to interact with these systems. However, when the object-link mismatch problem occurs, SQL is not the best way to express the access mode. For example, relational databases cannot work well in the hot Big Data Field.

Common definitions of big data include: first, big data means that the data is big enough. You have to study it to get some insights from the data. Second, big data is no longer applicable to data on a single machine. These ideas are incomplete. We need to consider data in a fundamentally different way and consider data from the perspective of how to drive commercial value. Such data is big data.

In the big data field, the system must be able to adapt to different types of data formats and data sources, without the need to strictly define the mode in advance, and be able to process large-scale data. In this way, NoSQL emerged.

Ii. NoSQL Definition

NoSQL (NoSQL = Not Only SQL), meaning "Not just SQL", is a brand new revolutionary database movement. NoSQL advocates the use of non-relational data storage. Most database technologies do not support ACID (atomicity, consistency, isolation, and durability), and most of them are open-source projects, known as NoSQL as a whole.

Iii. NoSQL Classification

NoSQL databases are generally divided into four categories: Key-Value storage database, column storage database, document database, and Graph database. Their data models, advantages and disadvantages, and typical application scenarios are shown in table 1.

Table 1 NoSQL Database Analysis

Iv. Features of NoSQL

NoSQL databases do not have a unified architecture, but they all share some of the common features shown in table 2.

Table 2 NoSQL features

V. Common NoSQL Databases

Suitable for NoSQL databases: (1) simple data models; (2) IT systems with higher flexibility; (3) High database performance requirements; (4) high Data Consistency is not required. (5) for a given key, it is easier to map an environment with complex values.

Common NoSQL databases are shown in table 3.

Table 3 common NoSQL Databases