Database design in multi tenant mode

• One 、 Multi-tenant technology

  • Multi-Tenancy Technology Also known as multi tenancy Technology , It's a software architecture technique , It can be implemented in multiple users （ Users here mostly refer to enterprise users ） Share the same system or program components in the environment , And it can ensure the isolation of user data .
  • The core ： Realize the isolation of user data under the same set of procedures .
  • Multi tenancy technology is usually applied Saas Mode of software system ,Saas Mode software applications are uniformly deployed to the servers of service providers , Customers can pay according to their actual needs . stay SaaS The platform needs to use a common data center to provide the same or even customized services for most clients with a single system architecture and services , And it can still ensure the normal use of the data of each tenant . This greatly increases the difficulty of designing the system database .
  • Traditional software model is different from SaaS Comparison of software modes

• Two 、 Multi tenant database design

  • 1. Independent database
    • Each tenant has an independent database .
    • advantage ： It helps to simplify the design difficulty of data model and database , High level of data isolation , Good safety , Data recovery in case of failure is relatively simple .
    • shortcoming ： Increased the number of database installations , Resulting in increased acquisition and maintenance costs .
  • 2. Shared database , Independent Schema

    • Schema

      • stay oracle A database in can have multiple users , So a user usually corresponds to a Schema, Tables are built on Schema Medium . there Schema It can be understood as Oracle Users in , Create a user for each tenant .
      • stay MySQL Medium Schema A special , His counterpart is MySQL Different databases under the instance database.
    • Multiple or all tenants share a database service , Create one for each tenant database or schema.
    • advantage ： High security , Provides a degree of logical data isolation , But it's not completely isolated , Each database can support more tenants , Cost savings .
    • shortcoming ： Because it involves the data of other tenants , It is difficult to recover data in case of failure ; Cross tenant data statistics are difficult .
  • 3. Shared database , Shared data table
    • All tenants share a database 、 A set of database tables , Add tenants to the table ID To identify which tenant the record belongs to .
    • advantage ： Because all tenants use a unified database, the cost is low .
    • shortcoming ： Lowest isolation level , Minimum safety , The system design 、 Database design is difficult , Data backup and recovery is the most difficult .