[英]Auto_increment ID in Java-Sqlite code
我試圖將SQLite與java結合使用,我編寫了一段給出三個String的代碼
必須填充表格
|---------------------|
|ID|NAME|SNAME1|SNAME2|
|1 |Ale |test |test2 |
|---------------------|
如何自動增加ID? 我試圖在創建表時使用auto_increment,但是在填充表時出現異常,因此我正在尋找一種實現此目的的好方法。
從代碼中可以看到,現在每次執行程序時,我只能插入一行。
package database;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;
/**
*
* @author MITROTTA
*/
public class Database {
/**
* @param args the command line arguments
*/
public static void main(String[] args) throws SQLException {
Connection c = null;
Statement stmt = null;
String sql;
//Variabili Database
String name;
String sname1, sname2;
Scanner in = new Scanner(System.in);
try {
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:test.db");
c.setAutoCommit(false);
System.out.println("Opened database successfully");
//Creazione tabella
stmt = c.createStatement();
sql = "CREATE TABLE IF NOT EXISTS COMPANY " +
"(ID INT PRIMARY KEY NOT NULL," +
" NAME CHAR(30) NOT NULL, " +
" SNAME1 CHAR(30) NOT NULL, " +
" SNAME2 TEXT)";
stmt.executeUpdate(sql);
System.out.print("Type name: ");
name = in.nextLine();
System.out.print("Type sname1: ");
sname1 = in.nextLine();
System.out.print("Type sname2: ");
sname2 = in.nextLine();
sql = "INSERT INTO COMPANY (ID,NAME,SNAME1,SNAME2) " +
"VALUES (2, '" + name + "','" + sname1 + "','" + sname2 + "');";
stmt.executeUpdate(sql);
ResultSet rs = stmt.executeQuery( "SELECT * FROM COMPANY;" );
while ( rs.next() ) {
int id = rs.getInt("ID");
String name1 = rs.getString("NAME");
String name2 = rs.getString("SNAME1");
String name3 = rs.getString("SNAME2");
System.out.println( "ID = " + id );
System.out.println( "Name = " + name1 );
System.out.println( "SName1 = " + name2 );
System.out.println( "SName3 = " + name3 );
System.out.println();
}
rs.close();
stmt.close();
c.commit();
c.close();
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Table created successfully");
}
}
要獲得自動遞增的列 ,您需要將其聲明為INTEGER PRIMARY KEY
(不是INT
)。
然后,您可以只插入一個NULL值,或者從INSERT語句中忽略該列。
只需在插入過程中使用NULL
值代替id
,並且可能不應該將其聲明為NOT NULL
。
資料來源: http : //www.sqlite.org/faq.html#q1
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