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create table roles (id int primary key);
create table permissions (id int primary key);
CREATE TABLE IF NOT EXISTS roles_permissions (
role_id INT(12) NOT NULL,
permission_id INT(12) NOT NULL,
UNIQUE KEY (role_id,permission_id),
CONSTRAINT `fk-rprole` FOREIGN KEY (`role_id`)
REFERENCES `roles`(`id`)
ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `fs_rppermission` FOREIGN KEY (`permission_id`)
REFERENCES `permissions` (`id`)
ON DELETE CASCADE ON UPDATE CASCADE
);