Self.

self.ipv4_address
self.private_ip

self.address
self.port

  provisioner "local-exec" {
   command = "mysql --host=${self.address} --port=${self.port} --user=${self.username} --password=${self.password} < ./schema.sql"
   }
 }

Related

 resource "aws_instance" "your_web" {
  # ...

  provisioner "local-exec" {
    command = "echo The server's IP address is ${self.private_ip}"
  }
}

resource "aws_instance" "web" {
  # ...

  provisioner "local-exec" {
    command    = "echo The server's IP address is ${self.private_ip}"
    on_failure = continue
  }
}

See also

• Terraform provisioner, self., local-exec, remote-exec, file