------------I do not have him, but the hand is ripe, humble and foolish, and eager to be hungry-------------
Common non-relational databases:
Mongo DB
Redis
HBase
Introduction to the two-dimensional table:
in the Relational Model , the data structure is represented as a two-dimensional table, a relationship is a two-dimensional table (but not any two-dimensional table can represent a relationship), the two-dimensional table name is the relationship name. The first row in the table is often referred to as the property name, and each tuple and attribute in the table is non-re-divided, and the order of tuples is irrelevant.
used in Relationship Terminology as follows:
Record each row in a two-dimensional table is called a record, or a tuple.
Field each column in a two-dimensional table is called a field, or a property.
The domain is the value range of the property .
The pros and cons of both:
Relational database:
It is easy to understand that the data stored in the database is stored in the form of a two-dimensional table!
a two-dimensional table is made up of rows and columns, knowing that the row and column numbers will be able to locate the data in the table! Excel is a two-dimensional table!
Easy to use, the basic common SQL language makes it easy to operate relational databases!
SQL is supported , so complex queries can be made!
easy to maintain, rich integrity (domain integrity, entity integrity, referential integrity, and custom integrity) greatly reduces data redundancy, and the ACID properties of transactions ensure data Consistency!
Low Read-write performance
The processing of massive data is inferior to that of non-relational database
The distribution is not perfect .
Non-relational database:
not supported SQL, eliminating the steps to parse SQL, high read and write performance
In the form of key-value pairs, data is not coupled and is highly scalable .
we can implement distributed processing of data .
the processing of the applicable Yu Hai volume data
the performance of persistence is low
because there is no transaction, the security of the data is not high .
the debut time is short, the function does not have relational database perfect
ORACLE-03: The advantages and disadvantages of relational database and non-relational database