JDBC

JDBC

자바로 OracleDB에 접속하기 위한 라이브러리
jdbc driver를 jdk와 OracleDB의 버전에 맞게 오라클 홈페이지에서 다운 받아 프로젝트의 build path에 등록


SELECT 등 DB를 조회하여 값을 가져올 때)
String url = "jdbc:oracle:thin:@아이피:1521/사용할디비이름";
String sql = "쿼리문";

Class.forName("oracle.jdbc.driver.OracleDriver");
Connection con = DriverManager.getConnection(url, "디비아이디", "디비암호");
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(sql);

// rs.next();
// column 한줄 씩 읽기
whie(rs.next()) {
int id = rs.getInt("ID");
System.out.println(id);
}

rs.close();
st.close();
con.close();


INSERT, UPDATE, DELETE 등 DB를 조작할 때)
String title = "TEST";
String writerId = "abcd";
String content = "wow";
String files = "";

String url = "jdbc:oracle:thin:@아이피:1521/사용할디비이름";
String sql = "INSERT INTO notice ("
+ "    title,"
+ "    writer_id,"
+ "    content,"
+ "    files"
+ ") VALUES (?,?,?,?)";

Class.forName("oracle.jdbc.driver.OracleDriver");
Connection con = DriverManager.getConnection(url, "디비아이디", "디비암호");
PreparedStatement st = con.prepareStatement(sql);
// 쿼리문의 ?에 index는 1부터 시작.
st.setString(1, title);
st.setString(2, writerId);
st.setString(3, content);
st.setString(4, files);
int result = st.executeUpdate();
// executeUpdate 메서드는 DML 실행된 Rows 정수 결과값을 반환한다.

System.out.println(result);

st.close();
con.close();

st.set타입(인덱스, 넣을값변수) 시 넣을값은 홑따옴표에 감싸인 값 형태로 들어간다.
명령문 형식으로 들어가길 바란다면 쿼리문을 "SELECT * FROM 테이블 WHERE " + 넣을값변수 + " LIKE~" 등으로 넣어준다