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.

create two database

CREATE database sampledb;

CREATE database sampledb2;

create table for both database

CREATE TABLE employee
    (
        id SERIAL PRIMARY KEY,
        name VARCHAR(255) NOT NULL,
        password VARCHAR(255),
        descr VARCHAR(255),
        gross_salary_month DOUBLE PRECISION,
        health_insurance_share DOUBLE PRECISION,
        surcharge DOUBLE PRECISION,
        type VARCHAR(255),
        working_contract VARCHAR(255),
        contract_hours_month DOUBLE PRECISION,
        limit_hours_month DOUBLE PRECISION,
        ref_id bigint,
        valid bigint
    );

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",
	"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
  }'

TenantTwo Testing :

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

	"name":"Emp1",
	"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
  }'