问题
What is the purpose of database schema? Where can I find more information about this? It's not table, it's not database, what is it?
回答1:
From the quackit.com tutorial – SQL Server - Database Schemas:
A database schema is a way to logically group objects such as tables, views, stored procedures etc. Think of a schema as a container of objects.
You can assign a user login permissions to a single schema so that the user can only access the objects they are authorized to access.
Schemas can be created and altered in a database, and users can be granted access to a schema. A schema can be owned by any user, and schema ownership is transferable.
回答2:
A SQL schema is container of objects. For example you may have a large enterprise application and then it's a good practice to use different schemas for different purposes (e.g. put HR related tables into HR schema, accounting related tables into Accounting schema and so on). A schema can be owned by any user, and the ownership is transferable.
回答3:
Your best answer is probably all over the interwebs, such as:
Database schema article in Wikipedia.
However, put simply, the database schema is the definition that describes the entire configuration of the database, including all of its tables, relations, index, etc.
回答4:
The logical schema is the structure of the tables and relationships in the database.
The physical one is how this structure and the data it holds are stored.
回答5:
A database schema is a name space. It is like the C++ namespace, Java namespace, Delphi unit, etc. Depending on the DBMS, it may allow:
- to grant / revoke access to namespace;
- to use fully qualified / short object name (.);
- to admin the schema as a unit;
- etc.
You have to go to the your DBMS vendor site and check the documentation for the Schema term. In most cases, that will be a topic in Concepts.
回答6:
It's like a folder where you can have tables and other objects inside
Here is some more on wikipedia
来源：https://stackoverflow.com/questions/2674222/what-is-purpose-of-database-schema