What are relational and non-relational databases? Introduction and comparison of two common types of databases

This article brings you what are relational and non-relational databases? The introduction and comparison of two common types of databases has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Relational database:

Oracle, DB2, Microsoft SQL Server, Microsoft Access, MySQL

Non-relational database:

NoSql, Cloudant, MongoDb, redis, HBase

The difference between the two databases:

Relational database

Characteristics of relational database

　1. Relational database refers to A database that uses relational model to organize data;

2. The biggest feature of relational database is transaction consistency;

3. Simply put, the relational model refers to the two-dimensional table model, and a relational database is a data organization composed of two-dimensional tables and the connections between them.

Advantages of relational database

1. Easy to understand: The two-dimensional table structure is very close to the logical world Concepts, relational models are easier to understand than other models such as network and hierarchical models;
2. Easy to use: The common SQL language makes it very convenient to operate relational databases;
3.Easy to maintain: Rich integrity (entity integrity, referential integrity and user-defined integrity) greatly reduces the probability of data redundancy and data inconsistency;
4. Supports SQL, can be used for complex queries.

Disadvantages of relational database

1. The huge price paid to maintain consistency is its poor read and write performance;
2. Fixed table structure ;
3. High concurrent reading and writing requirements ;
4. Highly efficient reading and writing of massive data;

Non-relational database

Features of non-relational database

1. Use the key Value pair stores data;
2. Distributed ;
3. Generally does not support ACID features;
4. Non-relational databases are strictly It is not a database, it should be a collection of structured data storage methods.

Advantages of non-relational database

1. No need to parse through the sql layer, reading and writing performance is very high;
2. Based on key-value pairs, the data has no coupling, is easy to expand;
3. The format of storing data: the storage format of nosql is key, value form, document form, picture form, etc. Document form, picture form, etc., while relational databases only support basic types.

Disadvantages of non-relational databases

1. Does not provide sql support, and the cost of learning and using is high;
2.No transaction processing, additional functions bi and report support are not good;

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