Constraints

To ensure the stability and security of GaussDB(for MySQL), certain constraints are put in place for access or permission control. Table 1 and Table 2 describe such constraints.

**Table 1** Function constraints
Function	Constraint
GaussDB(for MySQL) access	If GaussDB(for MySQL) instances do not have EIPs bound, the instances must be in the same VPC subnet as the ECSs associated with these instances. Security group rules must be added to allow ECSs to access GaussDB(for MySQL) instances. By default, a GaussDB(for MySQL) instance cannot be accessed by an ECS in a different security group. To enable access, you must add an inbound rule to the GaussDB(for MySQL) security group. When adding the rule, set the protocol and port, respectively, to TCP and to the default database port of the instance. Default database port of GaussDB(for MySQL): For primary/standby instances, the default port is 3306. You can change it if you want to access GaussDB(for MySQL) through another port over a private or public network.
Database root permissions	Only the root permissions for primary/standby instances are available on the instance creation page.
Database parameter modification	Most parameters can be modified on the GaussDB(for MySQL) console.
Data migration	The mysqldump tool can be used to migrate data to GaussDB(for MySQL).
GaussDB(for MySQL) instance reboot	GaussDB(for MySQL) instances can only be rebooted on the GaussDB(for MySQL) console.
GaussDB(for MySQL) backup files	GaussDB(for MySQL) backup files are stored in OBS buckets and are not visible to you.

**Table 2** Naming constraints
Parameter	Constraint
DB instance name	The name can contain 4 to 64 characters and must start with a letter. Only letters, digits, hyphens (-), and underscores (_) are allowed.
Database name	The name can contain 1 to 64 characters. Only letters, digits, hyphens (-), and underscores (_) are allowed. The total number of hyphens (-) cannot exceed 10.
Non-administrator account	The account can contain 1 to 32 characters. Only letters, digits, and underscores (_) are allowed.
Password	The password can contain 8 to 32 characters and must consist of at least three types of the following characters: uppercase letters, lowercase letters, digits, and special characters (~!@#$%^*-_=+?,()&).
Parameter template name	The template name can contain 1 to 64 characters. Only letters (case-sensitive), digits, hyphens (-), underscores (_), and periods (.) are allowed.
Backup name	The backup name can consist of 4 to 64 characters and must start with a letter. Only letters (case-sensitive), digits, hyphens (-), and underscores (_) are allowed.