update sql

Author: RainbowDashy

schema/schema.sql

@@ -0,0 +1,120 @@
+CREATE TABLE employee (
+	emp_no      SERIAL NOT NULL,
+	birth_date  DATE NOT NULL,
+	first_name  TEXT NOT NULL,
+	last_name   TEXT NOT NULL,
+	gender      TEXT NOT NULL CHECK (gender IN('M', 'F')) NOT NULL,
+	hire_date   DATE NOT NULL,
+	PRIMARY KEY (emp_no)
+);
+
+CREATE INDEX idx_employee_hire_date ON employee (hire_date);
+
+CREATE TABLE department (
+	dept_no     TEXT NOT NULL,
+	dept_name   TEXT NOT NULL,
+	PRIMARY KEY (dept_no),
+	UNIQUE      (dept_name)
+);
+
+CREATE TABLE dept_manager (
+	emp_no      INT NOT NULL,
+	dept_no     TEXT NOT NULL,
+	from_date   DATE NOT NULL,
+	to_date     DATE NOT NULL,
+	FOREIGN KEY (emp_no) REFERENCES employee (emp_no) ON DELETE CASCADE,
+	FOREIGN KEY (dept_no) REFERENCES department (dept_no) ON DELETE CASCADE,
+	PRIMARY KEY (emp_no, dept_no)
+);
+
+CREATE TABLE dept_emp (
+	emp_no      INT NOT NULL,
+	dept_no     TEXT NOT NULL,
+	from_date   DATE NOT NULL,
+	to_date     DATE NOT NULL,
+	FOREIGN KEY (emp_no) REFERENCES employee (emp_no) ON DELETE CASCADE,
+	FOREIGN KEY (dept_no) REFERENCES department (dept_no) ON DELETE CASCADE,
+	PRIMARY KEY (emp_no, dept_no)
+);
+
+CREATE TABLE title (
+	emp_no      INT NOT NULL,
+	title       TEXT NOT NULL,
+	from_date   DATE NOT NULL,
+	to_date     DATE,
+	FOREIGN KEY (emp_no) REFERENCES employee (emp_no) ON DELETE CASCADE,
+	PRIMARY KEY (emp_no, title, from_date)
+); 
+
+CREATE TABLE salary (
+	emp_no      INT NOT NULL,
+	amount      INT NOT NULL,
+	from_date   DATE NOT NULL,
+	to_date     DATE NOT NULL,
+	FOREIGN KEY (emp_no) REFERENCES employee (emp_no) ON DELETE CASCADE,
+	PRIMARY KEY (emp_no, from_date)
+);
+
+CREATE INDEX idx_salary_amount ON salary (amount);
+
+CREATE TABLE audit (
+    id SERIAL PRIMARY KEY,
+    operation TEXT NOT NULL,
+    query TEXT,
+    user_name TEXT NOT NULL,
+    changed_at TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE INDEX idx_audit_operation ON audit (operation);
+CREATE INDEX idx_audit_username ON audit (user_name);
+CREATE INDEX idx_audit_changed_at ON audit (changed_at);
+
+CREATE OR REPLACE FUNCTION log_dml_operations() RETURNS TRIGGER AS $$
+BEGIN
+    IF (TG_OP = 'INSERT') THEN
+        INSERT INTO audit (operation, query, user_name)
+        VALUES ('INSERT', current_query(), current_user);
+        RETURN NEW;
+    ELSIF (TG_OP = 'UPDATE') THEN
+        INSERT INTO audit (operation, query, user_name)
+        VALUES ('UPDATE', current_query(), current_user);
+        RETURN NEW;
+    ELSIF (TG_OP = 'DELETE') THEN
+        INSERT INTO audit (operation, query, user_name)
+        VALUES ('DELETE', current_query(), current_user);
+        RETURN OLD;
+    END IF;
+    RETURN NULL;
+END;
+$$ LANGUAGE plpgsql;
+
+-- only log update and delete, otherwise, it will cause too much change.
+CREATE TRIGGER salary_log_trigger
+AFTER UPDATE OR DELETE ON salary
+FOR EACH ROW
+EXECUTE FUNCTION log_dml_operations();
+
+CREATE OR REPLACE VIEW dept_emp_latest_date AS
+SELECT
+	emp_no,
+	MAX(
+		from_date) AS from_date,
+	MAX(
+		to_date) AS to_date
+FROM
+	dept_emp
+GROUP BY
+	emp_no;
+
+-- shows only the current department for each employee
+CREATE OR REPLACE VIEW current_dept_emp AS
+SELECT
+	l.emp_no,
+	dept_no,
+	l.from_date,
+	l.to_date
+FROM
+	dept_emp d
+	INNER JOIN dept_emp_latest_date l ON d.emp_no = l.emp_no
+		AND d.from_date = l.from_date
+		AND l.to_date = d.to_date;

schema/users.sql

@@ -1,4 +1,4 @@
-CREATE TABLE IF NOT EXISTS users (
+CREATE TABLE users (
     id SERIAL PRIMARY KEY,
     name VARCHAR(255) NOT NULL,
     email VARCHAR(255) NOT NULL UNIQUE