Apsara stack Database

1. The database file can only be one element (database file name), and the database service can create multiple database files.

2. A database is a data table and a data table is also a table name. A database file can have multiple tables.

3. The data table contains a row of column names, and a table can contain multiple rows of data.

 

The current database is basically in this mode, and then forms a two-dimensional table through the link.

A A1 A2 A3

B B1 B2

C C1 C2 C3...

 

V A1 A2 B1 C3 c4 ....

Multiple tables (two-dimensional) form a one-dimensional table, or a one-dimensional table, which is split into a two-dimensional table. A one-dimensional field coupled with a row number is also called a two-dimensional table.

 

But is this a real two-dimensional table? No!

The essence of the Two-dimensional table is XY dual-axis positioning.

Assume that the 20 field Relational Tables are

A1 A2 A3 A4

B1...

C1 ....

D1...

E1 E2 E3 E4

But the real tables should be wide.

Rn A1 A2 A3 A4

B1

B2

B3

B4

But how can we implement attribute settings for such tables?

 

Also, howProgramming LanguageIs the object migrated to the database?

Data Type Structure table object class library object nested set

Make the database a programming

Miscellaneous...

 

Conclusion: The operating system is the largest and most comprehensive data manager.