How much do you know about the theoretical knowledge of oracle?

Database software products:

1. Small database

Access                         Foxbase

 

2. Medium database

MYSQL                        MSSQLSEVER

 

3. Large databases

Sybase                         Oracle                       DB2

 

The composition of oracle:

1.oracle server 2.oracle instance 3.oracle client

 

oracle database structure

1. Physical structure: refers to the files we can see, the files that store data

 

1) Control file: record the path of the data file, control the data file

2) Log file: store the operation log related to the database

3) Data file: store data

4) Parameter file: the control file that controls the call

 

2. Logical structure

 

1. Tablespace 2. Table 3. Area 4. Segment 5. Data block

 

3. Memory structure

   Shared Pool: Compiled Scripting Language

   log buffer: buffer logs

   Java Pool Stream Pool .....

   PGA : Program Global Area : Resources occupied by a single user (bedroom)

   Data buffer: buffer the data read from the data file on the disk and store it in the memory. The main function is to improve the efficiency of querying data.