Constraints

To ensure the stability and security of TaurusDB, certain constraints are put in place for access or permission control. For details, see Table 1 and Table 2.

**Table 1** Function constraints
Function	Constraint
TaurusDB access	If TaurusDB 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 TaurusDB instances. By default, a TaurusDB instance cannot be accessed by an ECS in a different security group. To enable access, you must add an inbound rule to the TaurusDB 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 TaurusDB: For cluster instances, the default port is 3306. You can change it if you want to access TaurusDB through another port over a private or public network.
Database root permissions	Only the root permissions for cluster instances are available on the instance creation page.
Database parameter modification	Most parameters can be modified on the TaurusDB console.
Data migration	The mysqldump tool can be used to migrate data to TaurusDB.
TaurusDB instance reboot	TaurusDB instances can only be rebooted on the TaurusDB console.
TaurusDB backup files	TaurusDB backup files are stored in OBS buckets and are not visible to you.
Small-scale instances	For TaurusDB instances with 2 vCPUs and 8 GB memory, there are a maximum of 300,000 tables in a single instance and a maximum of 5,000 tables in a single database.

**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.
Reserved keywords	In addition to the reserved keywords of MySQL 8.0 Community Edition, some other reserved keywords are added to TaurusDB. Do not use these keywords when naming objects to prevent errors.