The characteristics of relational and non-relational databases and their advantages and disadvantages __ Database

Database Type	Characteristics	Advantages	Disadvantages
relational database SQLite, Oracle, MySQL	1, relational database, refers to the use of a relational model to organize Database of data; 2, the most characteristic of relational database is the consistency of affairs; 3, in simple terms, the relational model refers to the two-dimensional table model, A relational database is a data organization composed of two dimensional tables and the connection between them.	1, easy to understand: Two-dimensional table structure is very close to the logic of the world a concept, the relationship model relative to the network, level and other models are easier to understand; 2, easy to use: Universal SQL language makes operation of relational database very convenient; 3, easy to maintain: rich integrity (Entity integrity, referential integrity and user-defined integrity) greatly reduce the data redundancy and data inconsistency probability; 4, support SQL, can be used for complex queries.	1, in order to maintain the consistency of the huge cost is that its read and write performance is relatively poor; 2, fixed table structure; 3, high concurrent reading and writing needs; 4. High-efficient reading and writing of massive data;
Non-relational database MongoDb, Redis, HBase	1, the use of key value to store data; 2, distributed; 3, generally does not support the acid characteristic; 4, the non-relational database is strictly not a database, it should be a data structure of the collection of storage methods.	1, no need to go through the SQL layer parsing, read-write performance is very high; 2, based on the key-value pairs, the data is not coupled, easy to expand; 3, the format of storing data: NoSQL storage format is key,value form, document form, picture form and so on, document form, picture form and so on, but relational database only supports base type.	1, does not provide the SQL support, the study and the use cost is high; 2, no transaction processing, additional functions such as BI and reports and other support is not good;

Note 1: Database transactions must have ACID properties, acid is atomic atomicity, consistency consistency, isolation isolation, durability persistence.

Note 2: Persistent storage of data, especially the persistent storage of massive data, or the need for a relational database.