Oracle Database First Day

1. Oracle Database

Charge database, strong data processing capability, high security

2. The language of the operating database

SQL language, the standard of execution is the SQL99 standard

3. Products of the database

① charges: Oracle, SQL Server, DB2 ...

② Free: MYSQL ...

4. Structure type of Oracle database

c/S structure (need to have client on this machine)

5. Oracle database users with the highest permissions

SYS user, followed by system user

6. Logical type of database

Hierarchical type, net type, relational type

--The first two are obsolete, the relational type is the mainstream database on the market, and the frontier research trend is the object type database.

--Of course, the Oracle database we learned is a relational database.

7 Characteristics of a relational database (the form of a two-dimensional table exists)

Table (performance entity, also can represent the relationship between entities)
Table: Table name--Entity
Columns, Fields: Properties--Properties of entities
Line, record: specific entity--the data of the entity

8. Data in the SQL language operations database

①DQL: Data query Statement select query
②DML: Data manipulation Statement Insert update Delete new, UPDATE, delete

③DDL: Data Definition Statement Action database object (e.g. table) build table, delete table, modify table ...
④TCL: The concept of transaction control statement transactions
⑤DCL: Data Control statement management operations

9. Notes

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Oracle Database First Day