{"id":26450,"date":"2024-10-27T10:52:43","date_gmt":"2024-10-27T10:52:43","guid":{"rendered":"http:\/\/atmokpo.com\/w\/?p=26450"},"modified":"2024-11-26T07:42:39","modified_gmt":"2024-11-26T07:42:39","slug":"%ec%8a%a4%ed%94%84%eb%a7%81-%eb%b6%80%ed%8a%b8-%eb%b0%b1%ec%97%94%eb%93%9c-%ea%b0%9c%eb%b0%9c-%ea%b0%95%ec%a2%8c-sql%ec%9d%b4%eb%9e%80","status":"publish","type":"post","link":"https:\/\/atmokpo.com\/w\/26450\/","title":{"rendered":"\uc2a4\ud504\ub9c1 \ubd80\ud2b8 \ubc31\uc5d4\ub4dc \uac1c\ubc1c \uac15\uc88c, SQL\uc774\ub780"},"content":{"rendered":"

<\/p>\n

\uc2a4\ud504\ub9c1 \ubd80\ud2b8(Spring Boot)\ub294 \uc790\ubc14 \uae30\ubc18\uc758 \uc6f9 \uc5b4\ud50c\ub9ac\ucf00\uc774\uc158\uc744 \uc27d\uac8c \uac1c\ubc1c\ud560 \uc218 \uc788\ub3c4\ub85d \ub3c4\uc640\uc8fc\ub294 \ud504\ub808\uc784\uc6cc\ud06c\uc785\ub2c8\ub2e4. \uc774 \uac15\uc88c\uc5d0\uc11c\ub294 \uc2a4\ud504\ub9c1 \ubd80\ud2b8 \ubc31\uc5d4\ub4dc \uac1c\ubc1c\uc5d0 \ud544\uc218\uc801\uc778 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uae30\uc220 \uc911 \ud558\ub098\uc778 SQL(Structured Query Language)\uc5d0 \ub300\ud574 \uc0c1\uc138\ud788 \uc54c\uc544\ubcf4\ub3c4\ub85d \ud558\uaca0\uc2b5\ub2c8\ub2e4. SQL\uc740 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640 \uc0c1\ud638\uc791\uc6a9\ud558\uae30 \uc704\ud55c \ud45c\uc900 \uc5b8\uc5b4\ub85c, \ub370\uc774\ud130\ub97c \uc0bd\uc785, \uc870\ud68c, \uc218\uc815, \uc0ad\uc81c\ud558\ub294 \ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4.<\/p>\n

1. SQL\uc758 \ud544\uc694\uc131<\/h2>\n

\ud604\ub300\uc758 \uc5b4\ud50c\ub9ac\ucf00\uc774\uc158\uc5d0\uc11c \ub370\uc774\ud130\ub294 \uc911\uc694\ud55c \uc790\uc6d0\uc785\ub2c8\ub2e4. \uc0ac\uc6a9\uc790 \uc815\ubcf4, \uac70\ub798 \ub370\uc774\ud130, \ub85c\uadf8 \ub4f1 \ub2e4\uc591\ud55c \uc815\ubcf4\ub97c \uc800\uc7a5\ud558\uace0 \uc774\ub97c \ud6a8\uacfc\uc801\uc73c\ub85c \uad00\ub9ac\ud558\ub294 \uac83\uc774 \ud544\uc218\uc801\uc785\ub2c8\ub2e4. SQL\uc740 \uc774\ub7ec\ud55c \ub370\uc774\ud130\ubca0\uc774\uc2a4\ub97c \uad00\ub9ac\ud558\ub294 \ub370 \ub9e4\uc6b0 \uc720\uc6a9\ud55c \ub3c4\uad6c\ub85c, SQL\uc744 \ud1b5\ud574 \uac1c\ubc1c\uc790\ub294 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640 \ud6a8\uc728\uc801\uc73c\ub85c \uc0c1\ud638\uc791\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n

2. SQL\uc758 \uc5ed\uc0ac<\/h2>\n

SQL\uc740 1970\ub144\ub300 \ucd08\ubc18 IBM\uc758 \uc5d0\ub4dc\uac70 F. \ucf54\ub4dc\uc5d0 \uc758\ud574 \uac1c\ubc1c\ub418\uc5c8\uc2b5\ub2c8\ub2e4. \ucd08\uae30\uc758 SQL\uc740 \uad00\uacc4\ud615 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uad00\ub9ac\ub97c \uc704\ud55c \uc5b8\uc5b4\ub85c \uc124\uacc4\ub418\uc5c8\uc73c\uba70, 1986\ub144\uc5d0\ub294 ANSI(\ubbf8\uad6d \uad6d\uac00\ud45c\uc900\ud611\ud68c)\uc640 ISO(\uad6d\uc81c\ud45c\uc900\ud654\uae30\uad6c)\uc5d0 \uc758\ud574 \ud45c\uc900\ud654\ub418\uc5c8\uc2b5\ub2c8\ub2e4. \uc774\ud6c4 SQL\uc740 \ubc1c\uc804\uc744 \uac70\ub4ed\ud558\uba70 \ub2e4\uc591\ud55c \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc2dc\uc2a4\ud15c\uc5d0\uc11c \ub110\ub9ac \uc0ac\uc6a9\ub418\uace0 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n

3. SQL\uc758 \uae30\ubcf8 \uad6c\uc870<\/h2>\n

SQL\uc740 \uc8fc\ub85c \uba85\ub839\ubb38\uc744 \uc0ac\uc6a9\ud558\uc5ec \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640 \uc0c1\ud638\uc791\uc6a9\ud569\ub2c8\ub2e4. \uae30\ubcf8\uc801\uc73c\ub85c SQL \uba85\ub839\ubb38\uc740 CRUD(Create, Read, Update, Delete) \uc791\uc5c5\uc73c\ub85c \ub098\ub20c \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n

3.1 CREATE: \ub370\uc774\ud130 \uc0bd\uc785<\/h3>\n

CREATE \uba85\ub839\uc740 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc5d0 \uc0c8\ub85c\uc6b4 \ub370\uc774\ud130\ub97c \ucd94\uac00\ud558\ub294 \ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4. \uc608\ub97c \ub4e4\uc5b4, \uc544\ub798\uc758 SQL \ubb38\uc740 \uc0ac\uc6a9\uc790 \uc815\ubcf4\ub97c \ud3ec\ud568\ud558\ub294 \ud14c\uc774\ube14\uc5d0 \uc0c8\ub85c\uc6b4 \ub808\ucf54\ub4dc\ub97c \uc0bd\uc785\ud569\ub2c8\ub2e4.<\/p>\n

INSERT INTO users (username, password, email)\nVALUES ('user1', 'pass123', 'user1@example.com');<\/code><\/pre>\n
3.2 READ: \ub370\uc774\ud130 \uc870\ud68c<\/h3>\n
READ \uba85\ub839\uc740 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc5d0 \uc800\uc7a5\ub41c \ub370\uc774\ud130\ub97c \uc870\ud68c\ud558\ub294 \ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4. SELECT \ubb38\uc744 \uc774\uc6a9\ud558\uc5ec \ud2b9\uc815 \uc870\uac74\uc5d0 \ub9de\ub294 \ub370\uc774\ud130\ub97c \uac00\uc838\uc62c \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
SELECT * FROM users WHERE email = 'user1@example.com';<\/code><\/pre>\n
3.3 UPDATE: \ub370\uc774\ud130 \uc218\uc815<\/h3>\n
UPDATE \uba85\ub839\uc740 \uae30\uc874 \ub370\uc774\ud130\ub97c \uc218\uc815\ud558\ub294 \ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4. \uc544\ub798\uc758 SQL \ubb38\uc740 \ud2b9\uc815 \uc0ac\uc6a9\uc790\uc758 \ud328\uc2a4\uc6cc\ub4dc\ub97c \uc5c5\ub370\uc774\ud2b8\ud558\ub294 \uc608\uc2dc\uc785\ub2c8\ub2e4.<\/p>\n
UPDATE users\nSET password = 'newpass456'\nWHERE username = 'user1';<\/code><\/pre>\n
3.4 DELETE: \ub370\uc774\ud130 \uc0ad\uc81c<\/h3>\n
DELETE \uba85\ub839\uc740 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc5d0\uc11c \ub808\ucf54\ub4dc\ub97c \uc0ad\uc81c\ud558\ub294 \ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4. \ub2e4\uc74c SQL \ubb38\uc740 \ud2b9\uc815 \uc0ac\uc6a9\uc790\ub97c \uc0ad\uc81c\ud558\ub294 \uc608\uc2dc\uc785\ub2c8\ub2e4.<\/p>\n
DELETE FROM users\nWHERE username = 'user1';<\/code><\/pre>\n
4. SQL\uc758 \uc8fc\uc694 \uad6c\uc131 \uc694\uc18c<\/h2>\n
SQL\uc740 \uc5ec\ub7ec \uac00\uc9c0 \uad6c\uc131 \uc694\uc18c\ub85c \uc774\ub8e8\uc5b4\uc838 \uc788\uc2b5\ub2c8\ub2e4. \uc5ec\uae30\uc5d0\uc11c\ub294 SQL\uc758 \uae30\ubcf8\uc801\uc778 \uad6c\uc131 \uc694\uc18c\uc5d0 \ub300\ud574 \uc124\uba85\ud558\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n
4.1 \ub370\uc774\ud130 \uc815\uc758 \uc5b8\uc5b4(DDL)<\/h3>\n
\ub370\uc774\ud130 \uc815\uc758 \uc5b8\uc5b4\ub294 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uac1d\uccb4(\ud14c\uc774\ube14, \ubdf0, \uc778\ub371\uc2a4 \ub4f1)\uc758 \uc815\uc758\uc640 \uad00\ub828\ub41c \uba85\ub839\uc5b4\ub97c \ud3ec\ud568\ud569\ub2c8\ub2e4. DDL \uba85\ub839\uc5b4\uc758 \uc608\ub85c\ub294 CREATE, DROP, ALTER \ub4f1\uc774 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
4.2 \ub370\uc774\ud130 \uc870\uc791 \uc5b8\uc5b4(DML)<\/h3>\n
\ub370\uc774\ud130 \uc870\uc791 \uc5b8\uc5b4\ub294 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \ub0b4\uc758 \ub370\uc774\ud130\ub97c \uc870\uc791\ud558\ub294 \ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4. DML \uba85\ub839\uc5b4\uc5d0\ub294 INSERT, SELECT, UPDATE, DELETE \ub4f1\uc774 \ud3ec\ud568\ub429\ub2c8\ub2e4.<\/p>\n
4.3 \ub370\uc774\ud130 \uc81c\uc5b4 \uc5b8\uc5b4(DCL)<\/h3>\n
\ub370\uc774\ud130 \uc81c\uc5b4 \uc5b8\uc5b4\ub294 \ub370\uc774\ud130\uc5d0 \ub300\ud55c \uad8c\ud55c\uc744 \uad00\ub9ac\ud558\ub294 \ub370 \uc0ac\uc6a9\ub429\ub2c8\ub2e4. GRANT\uc640 REVOKE \uba85\ub839\uc5b4\uac00 \uc774\uc5d0 \ud574\ub2f9\ud569\ub2c8\ub2e4.<\/p>\n
5. \uad00\uacc4\ud615 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640 SQL<\/h2>\n
SQL\uc740 \uc8fc\ub85c \uad00\uacc4\ud615 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc5d0\uc11c \uc0ac\uc6a9\ub429\ub2c8\ub2e4. \uad00\uacc4\ud615 \ub370\uc774\ud130\ubca0\uc774\uc2a4\ub294 \ub370\uc774\ud130\ub97c \ud14c\uc774\ube14 \ud615\uc2dd\uc73c\ub85c \uc800\uc7a5\ud558\uba70, \uac01 \ud14c\uc774\ube14\uc740 \ud589\uacfc \uc5f4\ub85c \uad6c\uc131\ub418\uc5b4 \uc788\uc2b5\ub2c8\ub2e4. \ub370\uc774\ud130\ub294 \uae30\ubcf8 \ud0a4(primary key)\uc640 \uc678\ub798 \ud0a4(foreign key)\ub97c \ud1b5\ud574 \ud14c\uc774\ube14 \uac04\uc5d0 \uad00\uacc4\ub97c \ud615\uc131\ud569\ub2c8\ub2e4. \uc774\ub97c \ud1b5\ud574 \ub370\uc774\ud130\uc758 \ubb34\uacb0\uc131\uacfc \uc77c\uad00\uc131\uc744 \uc720\uc9c0\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
6. \uc2a4\ud504\ub9c1 \ubd80\ud2b8\uc640 SQL<\/h2>\n
\uc2a4\ud504\ub9c1 \ubd80\ud2b8\uc5d0\uc11c\ub294 JPA(Java Persistence API)\ub97c \ud1b5\ud574 SQL \uc791\uc5c5\uc744 \uc27d\uac8c \ucc98\ub9ac\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. JPA\ub294 \uac1d\uccb4 \uc9c0\ud5a5 \ud504\ub85c\uadf8\ub798\ubc0d \uc5b8\uc5b4\uc778 \uc790\ubc14\uc5d0\uc11c \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640\uc758 \uc0c1\ud638\uc791\uc6a9\uc744 \uac04\ud3b8\ud558\uac8c \ub9cc\ub4e4\uc5b4\uc8fc\ub294 \ud45c\uc900\uc785\ub2c8\ub2e4. JPA\ub97c \uc0ac\uc6a9\ud558\uba74 SQL \ubb38\uc744 \uc9c1\uc811 \uc791\uc131\ud558\uc9c0 \uc54a\uace0\ub3c4 \uac1d\uccb4\ub97c \uc800\uc7a5\ud558\uace0 \uc870\ud68c\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774 \uacfc\uc815\uc5d0\uc11c Hibernate\uc640 \uac19\uc740 ORM(Object-Relational Mapping) \ud504\ub808\uc784\uc6cc\ud06c\uac00 \ud568\uaed8 \uc0ac\uc6a9\ub420 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
6.1 \uc758\uc874\uc131 \ucd94\uac00<\/h3>\n
\uc2a4\ud504\ub9c1 \ubd80\ud2b8 \ud504\ub85c\uc81d\ud2b8\uc5d0\uc11c JPA\ub97c \uc0ac\uc6a9\ud558\uae30 \uc704\ud574\uc11c\ub294 \uba3c\uc800 Gradle\uc774\ub098 Maven\uc744 \ud1b5\ud574 \uc758\uc874\uc131\uc744 \ucd94\uac00\ud574\uc57c \ud569\ub2c8\ub2e4. Gradle\uc744 \uc0ac\uc6a9\ud558\ub294 \uacbd\uc6b0, \uc544\ub798\uc758 \uc758\uc874\uc131\uc744 build.gradle<\/code> \ud30c\uc77c\uc5d0 \ucd94\uac00\ud569\ub2c8\ub2e4.<\/p>\n
dependencies {\n    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'\n    runtimeOnly 'com.h2database:h2' \/\/ H2 \ub370\uc774\ud130\ubca0\uc774\uc2a4\ub97c \uc0ac\uc6a9\ud560 \uacbd\uc6b0\n}<\/code><\/pre>\n
6.2 \uc5d4\ud2f0\ud2f0(Entity) \uc815\uc758<\/h3>\n
JPA\ub97c \uc0ac\uc6a9\ud558\uc5ec \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640 \ub9e4\ud551\ub418\ub294 \ud074\ub798\uc2a4(\uc5d4\ud2f0\ud2f0)\ub97c \uc815\uc758\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc544\ub798\ub294 \uc0ac\uc6a9\uc790 \uc815\ubcf4\ub97c \ub098\ud0c0\ub0b4\ub294 \uc5d4\ud2f0\ud2f0\uc758 \uc608\uc2dc\uc785\ub2c8\ub2e4.<\/p>\n
import javax.persistence.Entity;\nimport javax.persistence.GeneratedValue;\nimport javax.persistence.GenerationType;\nimport javax.persistence.Id;\n\n@Entity\npublic class User {\n    @Id\n    @GeneratedValue(strategy = GenerationType.IDENTITY)\n    private Long id;\n    private String username;\n    private String password;\n    private String email;\n    \n    \/\/ Getters and Setters\n}<\/code><\/pre>\n
6.3 Repository \uc778\ud130\ud398\uc774\uc2a4 \uc0dd\uc131<\/h3>\n
JPA\uc5d0\uc11c\ub294 Repository \uc778\ud130\ud398\uc774\uc2a4\ub97c \ud1b5\ud574 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640\uc758 \uc0c1\ud638\uc791\uc6a9\uc744 \uad00\ub9ac\ud569\ub2c8\ub2e4. \uc544\ub798\ub294 \uc0ac\uc6a9\uc790 \ub370\uc774\ud130\ub97c \ucc98\ub9ac\ud558\uae30 \uc704\ud55c Repository \uc778\ud130\ud398\uc774\uc2a4\uc758 \uc608\uc2dc\uc785\ub2c8\ub2e4.<\/p>\n
import org.springframework.data.jpa.repository.JpaRepository;\n\npublic interface UserRepository extends JpaRepository {\n    User findByUsername(String username);\n}<\/user,><\/code><\/pre>\n
6.4 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc791\uc5c5 \uc218\ud589<\/h3>\n
\uc11c\ube44\uc2a4 \ud074\ub798\uc2a4\uc5d0\uc11c Repository\ub97c \uc8fc\uc785\ubc1b\uc544 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc791\uc5c5\uc744 \uc218\ud589\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc608\ub97c \ub4e4\uc5b4, \uc0ac\uc6a9\uc790\ub97c \ub4f1\ub85d\ud558\ub294 \uc11c\ube44\uc2a4 \uba54\uc18c\ub4dc\ub97c \ub2e4\uc74c\uacfc \uac19\uc774 \uad6c\ud604\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
import org.springframework.beans.factory.annotation.Autowired;\nimport org.springframework.stereotype.Service;\n\n@Service\npublic class UserService {\n    @Autowired\n    private UserRepository userRepository;\n\n    public User registerUser(String username, String password, String email) {\n        User user = new User();\n        user.setUsername(username);\n        user.setPassword(password);\n        user.setEmail(email);\n        return userRepository.save(user);\n    }\n}<\/code><\/pre>\n
7. SQL \ud29c\ub2dd \ubc0f \ucd5c\uc801\ud654<\/h2>\n
\ud6a8\uc728\uc801\uc778 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uc791\uc5c5\uc744 \uc704\ud574\uc11c\ub294 SQL \ud29c\ub2dd\uacfc \ucd5c\uc801\ud654\uac00 \ud544\uc218\uc801\uc785\ub2c8\ub2e4. \uc5ec\uae30\uc5d0\uc11c\ub294 SQL \uc131\ub2a5\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\ub294 \uba87 \uac00\uc9c0 \uae30\ubcf8\uc801\uc778 \ubc29\ubc95\uc744 \uc18c\uac1c\ud558\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n
7.1 \uc778\ub371\uc2a4(Index) \uc0ac\uc6a9<\/h3>\n
\uc778\ub371\uc2a4\ub97c \uc0ac\uc6a9\ud558\uba74 \ub370\uc774\ud130 \uac80\uc0c9 \uc18d\ub3c4\ub97c \ub192\uc77c \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc778\ub371\uc2a4\ub294 \ud2b9\uc815 \uc5f4\uc5d0 \ub300\ud55c \uac80\uc0c9 \uc131\ub2a5\uc744 \ud5a5\uc0c1\uc2dc\ucf1c\uc8fc\uba70, WHERE \uc808\uc5d0\uc11c \uc790\uc8fc \uc0ac\uc6a9\ub418\ub294 \uc5f4\uc5d0 \uc778\ub371\uc2a4\ub97c \ucd94\uac00\ud558\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4.<\/p>\n
7.2 \ucffc\ub9ac \ucd5c\uc801\ud654<\/h3>\n
\ubcf5\uc7a1\ud55c \ucffc\ub9ac\ub294 \uc131\ub2a5\uc5d0 \uc601\ud5a5\uc744 \uc904 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uac00\ub2a5\ud558\uba74 \ub2e8\uc21c\ud55c \ucffc\ub9ac\ub97c \uc0ac\uc6a9\ud558\uace0, JOIN\uc744 \ucd5c\uc18c\ud654\ud558\uace0, \uc11c\ube0c\ucffc\ub9ac \ub300\uc2e0 JOIN\uc744 \uc0ac\uc6a9\ud558\ub294 \uac83\uc774 \uc88b\uc2b5\ub2c8\ub2e4.<\/p>\n
7.3 \ub370\uc774\ud130 \uc815\uaddc\ud654<\/h3>\n
\uc815\uaddc\ud654\ub97c \ud1b5\ud574 \ub370\uc774\ud130\uc758 \uc911\ubcf5\uc131\uc744 \uc904\uc774\uace0 \ubb34\uacb0\uc131\uc744 \ub192\uc77c \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774\ub97c \ud1b5\ud574 \ub370\uc774\ud130\ubca0\uc774\uc2a4 \uad6c\uc870\ub97c \ud6a8\uc728\uc801\uc73c\ub85c \uc124\uacc4\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
8. \uacb0\ub860<\/h2>\n
\uc774\ubc88 \uac15\uc88c\uc5d0\uc11c \uc6b0\ub9ac\ub294 SQL\uc758 \uae30\ubcf8 \uac1c\ub150\uacfc \uc2a4\ud504\ub9c1 \ubd80\ud2b8\uc5d0\uc11c\uc758 \ud65c\uc6a9 \ubc29\ubc95\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf4\uc558\uc2b5\ub2c8\ub2e4. SQL\uc740 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640 \uc0c1\ud638\uc791\uc6a9\ud558\ub294 \uc911\uc694\ud55c \ub3c4\uad6c\uc774\uba70, \uc2a4\ud504\ub9c1 \ubd80\ud2b8\ub97c \ud1b5\ud574 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640 \uc27d\uac8c \uc5f0\ub3d9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. SQL\uc758 \uc774\ud574\ub294 \ubc31\uc5d4\ub4dc \uac1c\ubc1c\uc790\uc5d0\uac8c \ud544\uc218\uc801\uc774\uba70, \uc774\ub97c \ud1b5\ud574 \ud6a8\uc728\uc801\uc774\uace0 \uc548\uc815\uc801\uc778 \uc5b4\ud50c\ub9ac\ucf00\uc774\uc158\uc744 \uac1c\ubc1c\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc55e\uc73c\ub85c\uc758 \uac15\uc88c\uc5d0\uc11c\ub294 \uc2a4\ud504\ub9c1 \ubd80\ud2b8\uc758 \ub354\uc6b1 \uc2ec\ud654\ub41c \ub0b4\uc6a9\uacfc \uc2e4\uc81c \ud504\ub85c\uc81d\ud2b8 \uc801\uc6a9 \ubc29\ubc95\uc5d0 \ub300\ud574 \ub2e4\ub8f0 \uc608\uc815\uc774\ub2c8, \ub9ce\uc740 \uae30\ub300 \ubd80\ud0c1\ub4dc\ub9bd\ub2c8\ub2e4.<\/p>\n
9. \ucc38\uace0 \ubb38\ud5cc<\/h2>\n