Using DDL Statements to Create and Manage Tables

Database Objects :


Naming Rules :

Table names and column names:
– Must begin with a letter
– Must be 1–30 characters long
– Must contain only A–Z, a–z, 0–9, _, and $
– Must not duplicate the name of another object owned by the same user
– Must not be an PostgreSQL server reserved word

Read Consistency

Read Consistency :

• Read consistency guarantees a consistent view of the data at all times.
• Changes made by one user do not conflict with changes made by another user.
• Read consistency ensures that on the same data :
• Readers do not wait for writers
• Writers do not wait for readers

Implementation of Read Consistency :