Database structure for storing personal skills - database

Question

I need to design a database for storing skills for a person, a person can have none,one or several skills, what is a good way to store it when it comes to easy modification of skill and fast search?
I have been thinking
1. use a bit array, each bit position represents a skill,
2. a relation table that each row link a person to a SKILL
3. each skill as a field in the table of the person
Any other suggestion or what should I aim for？

Answer 1

First, we need a persons table (all code examples use MySQL syntax):
CREATE TABLE IF NOT EXISTS `persons` (
`id` int unsigned NOT NULL AUTOINCREMENT,
`first_name` varchar(50) NOT NULL,
`last_name` varchar(50) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB Comment='Persons';
And pretend this is the data in the table:
|----|------------|-----------|
| id | first_name | last_name |
|----|------------|-----------|
| 1 | John | Doe |
| 2 | Benny | Hill |
| 3 | Linus | Torvalds |
| 4 | Donald | Knuth |
| .. | .......... | ......... |
|----|------------|-----------|
Then we need a skills table to hold all known skills:
CREATE TABLE IF NOT EXISTS `skills` (
`id` int unsigned NOT NULL AUTOINCREMENT,
`name` varchar(50) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB Comment='Skills';
|----|---------------|
| id | name |
|----|---------------|
| 1 | Swimming |
| 2 | Pilot |
| 3 | Writing |
| 4 | Create kernel |
| 5 | Astronaut |
| .. | ............. |
|----|---------------|
Finally we need a table that associates a person with a skill:
CREATE TABLE IF NOT EXISTS `persons_skills` (
`person_id` int unsigned NOT NULL,
`skill_id` int unsigned NOT NULL,
PRIMARY KEY (`person_id`, `skill_id`),
KEY (`person_id`),
KEY (`skill_id`)
) ENGINE=InnoDB Comment='Skills held by every person';
ALTER TABLE `persons_skills`
ADD FOREIGN KEY (`person_id`) REFERENCES `persons` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
ADD FOREIGN KEY (`skill_id`) REFERENCES `skills` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;
The primary key is defined so that no person can be associated with the same skill more than once and both columns are foreign key to their respective tables.
Assume the data below:
|-----------|----------|
| person_id | skill_id |
|-----------|----------|
| 1 | 1 |
| 2 | 1 |
| 2 | 2 |
| 3 | 1 |
| 3 | 4 |
| 4 | 2 |
| 4 | 3 |
| ......... | ........ |
|-----------|----------|
This data would indicate that John Doe, Benny Hill and Linus Torvalds all have the skill "Swimming". Benny Hill and Donald Knuth are both pilots. Linus Torvalds created a kernel. And Donald Knuth is a writer. None of the persons are an Astronaut...

Answer 2

It's a clasic many to many relationship so I would suggest a persons table, skills table and a personToSkill table. You other suggested solutions might be tempting at first, but they are both a maitnence hell.