Multitenancy:

A multitenant application is a shared resource that allows separate users, or "tenants," to view the application as though it was their own. A typical scenario that lends itself to a multitenant application is one in which all users of the application may wish to customize the user experience but otherwise have the same basic business requirements

Multitenant Models:

There are several models to achieve multitenancy in an application:

1)Database per Tenant: Each Tenant has its own database and is isolated from other tenants.

2)Shared database, Separate Schema: All Tenants share a database, but have their own database schemas and their own tables.

3)Shared Database, Shared Schema: All Tenants share a database and tables. Every table has a Column with the Tenant Identifier, that shows the owner of the row.

Think about it

1)Database per Tenant: Every Tenant has its own house.

2)Shared Database, Separate Schema: Every Tenant in the same building, but has its own apartment.

3)Shared Database, Shared Schema: Everyone is living in the same apartment and all stuff is marked with sticky-notes to show who owns it.

Every model is a trade-off between isolation and resource sharing.

This Application is used to create database and register new tenant runtime

There are centeral db which use to save runtime created database name and tenant. Purpose is , If server restart then older databsae and tenant id register .

CREATE database appdb;

CREATE TABLE "applicationdb" ("id" SERIAL NOT NULL, "tenant_id" CHARACTER VARYING(100), "database_name" CHARACTER VARYING(100), PRIMARY KEY ("id"));

application.properties - used to make some db related configration.

db.username=postgres db.password=postgres123 db.driverclass=org.postgresql.ds.PGSimpleDataSource db.url.Tenant=jdbc:postgresql://127.0.0.1:5432/

app.db=jdbc:postgresql://127.0.0.1:5432/appdb

**create database and register tenantID runtime **

curl -X POST \
  http://localhost:8080/tenant/create \
  -H 'cache-control: no-cache' \
  -H 'content-type: application/json' \
  -d '{
	"dbname":"sampledb1",
	"tenantID":"TenantOne"
}'

curl -X POST \
  http://localhost:8080/tenant/create \
  -H 'cache-control: no-cache' \
  -H 'content-type: application/json' \
  -d '{
	"dbname":"sampledb2",
	"tenantID":"TenantTwo"
}'

TenantOne Testing :

curl -X POST \
  http://localhost:8080/employees/create \
  -H 'cache-control: no-cache' \
  -H 'content-type: application/json' \
  -H 'x-tenantid: TenantOne' \
  -d '{

	"name":"Emp1 tenta two",
	"password":"12345",
	"descr":"Tet description",
	"gross_salary_month":2000,
	"health_insurance_share":2300,
	"surcharge":30,
	"type":"parmanent",
	"working_contract":"Long",
	"contract_hours_month":3,
	"limit_hours_month":3,
	"ref_id":2,
	"valid":0
}'