Why should you care?

Large OracleCore modules (payments, KYC, billing) ship as packages so teams share one API.

See it live — copy this example

Run these statements in SQL Developer or SQL*Plus against your lab PDB. Prefer a practice user — not SYS — for application SQL.

CREATE OR REPLACE PACKAGE account_pkg AS
  PROCEDURE credit(p_id NUMBER, p_amount NUMBER);
  FUNCTION get_bal(p_id NUMBER) RETURN NUMBER;
END account_pkg;
/

CREATE OR REPLACE PACKAGE BODY account_pkg AS
  PROCEDURE credit(p_id NUMBER, p_amount NUMBER) AS
  BEGIN
    UPDATE customers SET balance = balance + p_amount WHERE customer_id = p_id;
    COMMIT;
  END;

  FUNCTION get_bal(p_id NUMBER) RETURN NUMBER AS
    v NUMBER;
  BEGIN
    SELECT balance INTO v FROM customers WHERE customer_id = p_id;
    RETURN v;
  END;
END account_pkg;
/

BEGIN
  account_pkg.credit(1, 100);
END;
/
SELECT account_pkg.get_bal(1) FROM dual;

What happened?

• The package spec lists what others can call.
• The body contains the code.
• Call with package_name.procedure_name.

Practice next

1. Create the package spec, then the body.
2. Call credit and get_bal.
3. Describe account_pkg in SQL Developer.
4. Add a constant MIN_AMOUNT in the package.
5. Grant EXECUTE on account_pkg to a app user.

Remember

Packages bundle related APIs. Spec = contract; body = code. Call as package.member.

Payments API

Channel apps must not invent their own UPDATE statements.

Outcome: They call account_pkg only.