SQL Training - 01

Schema: is a description of the data 

schema is SQL is a group of tables 

you can create a user and give him a schema; this user can't see any other tables from sachems

SQL Server Databases:

1. Master: contains meta of all dbs 
2. Temp:
3. Model: Like polymorphism (Create tables (Like Lookups), views, stored procedures,... to be inherited in and newly created database)
4. Ms: It contains Jobs, Alerts,
5. Resource
6. Distribution 

You mustn't make any changes in Master and MS databases

Default Collations for Arabic:

Use Arabic_100_CI/CS_AS_KS_WS after that you don't need to use nvarchar as datatypes you can use varchar to store arabic values 

* You can create multi-files(.nDF) to store tables, each table could be stored in different group, for example create A1.nDF, A2.nDF files as group, and put table T1 in group 1

* Not recommend to use Shrink in database but still you can use it. 

Views:

• Lite
• Executed
• Ready to read
• High performance and low time to execute
• Separated Privileges
• Denormalization 
•  No parsing needed after created