introduction to nosql databases

Introduction to Oracle DatabaseMaybe a lot of people are familiar with SQL Server, not much about Oracle database, here is a brief introductionThe founder of Oracle database is Lawrence Ellis.Oracle database can be used by multiple operating systemsEg:windows,linux,solaris,aix, etc.Now let's make a simple comparison between Oracle and SQL ServerThe 1:oracle database supports more systems than SQL Server, and the SQL Server database is developed by Mic

with ANSI standards, they must collectively support some key keywords (such as SELECT, UPDATE, DELETE, INSERT, where, and so on) in a similar way But in addition to the SQL standard, most SQL database programs have their own private extensions RdbmsRDBMS refers to a relational database management system. The RDBMS is the foundation of SQL and is also the foundation of all modern database systems, such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access. Data in an RDBMS is stored in

1. What is a databaseDatabases: Database, the medium in which data is stored and processed efficiently (there are two main types of media: Disk and memory).2, the classification of the databaseDatabase based on the different storage media, can be divided into two categories: relational database (SQL) and non-relational database (Nosql:not only SQL, not relational database called non-relational database)3. What are the products in different database camps?relational databaseLarge: ORACLE,DB2Mediu

= ' female ', age=18 where uid=3 and Uname= ' Zhang Sanfeng ' Check Select column, column, column from table where condition * Represents all Columns SELECT * FROM MyUser where age>18; Column type Numeric type tinyint smallint int integer bigint Float double Character type Char 0~255 fixed-length characters Name Char (10) Space change time in ___ Insufficient right to fill the space on the query will be automatically removed varchar 0~65535 bytes If it is utf-8 a Chinese character to handle 21

allows nodes to have multiple parent nodes.Mesh model allows multiple connections between two nodes (composite contact)The mesh model can be more directly described in the real world.A hierarchical model is actually a special case of a mesh modelRelational modelrelational database system using relational model as data organization method1970 E.f.codd, a researcher at the San Jose Lab at IBM, first proposed a relational model of database systemsThe new database management system of computer vend