PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

Introducing MySQL’s Privilege System
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or
MAX_UPDATES_PER_HOUR n
or
MAX_CONNECTIONS_PER_HOUR n
These clauses allow you to limit the number of queries, updates, or connections per
hour a user may make.They can be useful for limiting individual user load on shared
systems.
Privileges are stored in five system tables, in the database called mysql.These five
tables are called mysql.user, mysql.db, mysql.host, mysql.tables_priv, and
mysql.columns_priv. As an alternative to GRANT, you can alter these tables directly.
We discuss exactly how these tables work and how you can alter them directly in
Chapter 12,“Advanced MySQL Administration.”
Types and Levels of Privileges
Three basic types of privileges exist in MySQL: privileges suitable for granting to regular
users, privileges suitable for administrators, and a couple of special privileges. Any user
can be granted any of these privileges, but it’s usually sensible to restrict the administrator
type privileges to administrators, according to the principle of least privilege.
You should grant privileges to users only for the databases and tables they need to
use.You should not grant access to the mysql database to anyone except an administrator.This
is the place where all the users, passwords, and so on are stored. (We look at this
database in Chapter 12.)
Privileges for regular users directly relate to specific types of SQL commands and
whether a user is allowed to run them.We discuss these SQL commands in detail in the
next chapter. For now, let’s look at a conceptual description of what they do.The basic
user privileges are shown in Table 9.1.The items under the Applies To column are the
objects to which privileges of this type can be granted.
Table 9.1 Privileges for Users
Privilege Applies To Description
SELECT tables, columns Allows users to select rows (records) from tables.
INSERT tables, columns Allows users to insert new rows into tables.
UPDATE tables, columns Allows users to modify values in existing table rows.
DELETE tables Allows users to delete existing table rows.
INDEX tables Allows users to create and drop indexes on particular tables.
ALTER tables Allows users to alter the structure of existing tables by, for
example, adding columns, renaming columns or tables, and
changing data types of columns.