Relational Database
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Non-relational databases
Relational database the most typical data structure is a table, and a data link between the organization of two-dimensional table consisting of
advantages:
1, easy to maintain: using a table structure is consistent format;
2, easy to use: SQL language general, for complex queries;
3, complicated operations: support the SQL can be used for very complex queries between a plurality of tables and a table.
Disadvantages:
1, read and write performance is relatively poor, especially efficient mass data read and write;
2, a fixed table structure, flexibility less impressive;
3, concurrent read and write high demand, the traditional relational database, the hard disk I / O is a big bottleneck.
Non-relational database strictly not a database, it should be for a collection of structured data storage method, can be a document or key-value pairs.
Advantages:
1, flexible format: The format of the stored data can be key, value form, the form of documents, pictures, forms, etc., in the form of documents, pictures, forms, etc., flexible, wide application scenarios, and relational database only support basic type .
2, speed: nosql random access memory or a hard disk may be used as a carrier, and a hard disk can use the relational database;
3, high scalability;
4, low cost: nosql database deployment simple, basically open source software.
Disadvantages:
1, sql does not provide support, learning and use of high cost;
2, no transaction;
3, a data structure is relatively complicated, complex queries from less impressive.
Classification and comparison of non-relational databases:
1, document type
2, key-value Type
3, database columns
4, the graphics database
Supplementary: Redis supports five data types: string (string), hash (hash), list (list), set (collection) and zset (sorted set: an ordered set).