|1||Keywords are written uppercase, names are written in lowercase.|
|2||3 space indention1.|
|3||One command per line.|
|5||Commas in front of separated elements.|
|6||Call parameters aligned, operators aligned, values aligned.|
|7||SQL keywords are right aligned within a SQL command.|
|8||Within a program unit only line comments
|9||Brackets are used when needed or when helpful to clarify a construct.|
PROCEDURE set_salary(in_employee_id IN employees.employee_id%TYPE) IS CURSOR c_employees(p_employee_id IN employees.employee_id%TYPE) IS SELECT last_name ,first_name ,salary FROM employees WHERE employee_id = p_employee_id ORDER BY last_name ,first_name; r_employee c_employees%ROWTYPE; l_new_salary employees.salary%TYPE; BEGIN OPEN c_employees(p_employee_id => in_employee_id); FETCH c_employees INTO r_employee; CLOSE c_employees; new_salary (in_employee_id => in_employee_id ,out_salary => l_new_salary); -- Check whether salary has changed IF r_employee.salary <> l_new_salary THEN UPDATE employees SET salary = l_new_salary WHERE employee_id = in_employee_id; END IF; END set_salary;
Inside a program unit only use the line commenting technique
-- unless you temporarly deactivate code sections for testing.
To comment the source code for later document generation, comments like
/** ... */ are used. Within these documentation comments, tags may be used to define the documentation structure.
Tools like ORACLE SQL Developer or PL/SQL Developer include documentation functionality based on a javadoc-like tagging.
||Description of a parameter.||
||Description of the return value of a function.||
||Describe errors that may be raised by the program unit.||
This is an example using the documentation capabilities of SQL Developer.
/** Check whether we passed a valid sql name @param in_name string to be checked @return in_name if the string represents a valid sql name @throws ORA-44003: invalid SQL name <b>Call Example:</b> <pre> SELECT TVDAssert.valid_sql_name('TEST') from dual; SELECT TVDAssert.valid_sql_name('123') from dual </pre> */
Tabs are not used because the indentation depends on the editor configuration. We want to ensure that the code looks the same, indepenent of the editor used. Hence, no tabs. But why not use 8 spaces? That's the traditional value for a tab. When writing a package function the code in the body has an indentation of 3. That's 24 characters as a starting point for the code. We think it's too much. Especially if we try to keep a line below 100 or 80 characters. Other good options would be 2 or 4 spaces. We settled for 3 spaces as a compromise. The indentation is still good visible, but does not use to much space. ↩