【发布时间】：2015-12-12 09:38:52
【问题描述】：
我不熟悉使用 DB 连接创建 Java 程序。我试图让程序创建一个表，读取一个表，以便我可以运行查询并显示某些数据。据我所知，我的程序已成功连接到数据库，但收到错误消息：
Syntax error: Encountered ")" at line 8, column 1.
Schema 'TEST' does not exist
Schema 'TEST' does not exist
Schema 'TEST' does not exist
Schema 'TEST' does not exist
其他错误，我习惯于接收 # 行，这样我至少知道从哪里开始查找。使用一行和一列 #，我不确定，我查看了其他帖子并尝试进行更新，例如将 APP 设为默认架构。关于从哪里开始寻找的正确方向的有益推动。一旦我弄清楚如何克服这个问题并打印查询，我知道我会很高兴的。感谢您提供的任何帮助。
import static java.lang.System.out;
import java.sql.*;
import java.sql.SQLException;
public class AnimalDB1 {
private static final String url = "jdbc:derby://localhost:1527/AnimalDB;create=true;user=test;password=test";
private static final String tableName = "Animal";
private static Connection conn = null;
private static int nextId = 1;
private boolean tablesCreated = false;
private static void createConnection(){
try{
System.out.println("Connecting to Database...");
conn = DriverManager.getConnection(url);
System.out.println("Database Connection Successful\n");
}
catch (SQLException e){}
}
// Increments the ID number for each animal
private void incId(){
AnimalDB1.nextId++;
}
private void animalTable() throws SQLException{
Statement statement = null;
try{
StringBuilder sb = new StringBuilder("");
sb.append("CREATE table Animal (\n");
sb.append("ID INTEGER NOT NULL,\n");
sb.append("AnimalName varchar(15),\n");
sb.append("Char1 varchar(15),\n");
sb.append("Char2 varchar(15),\n");
sb.append("Char3 varchar(15),\n");
sb.append("Char4 varchar(15),\n");
sb.append(")\n");
// Get a statement from the connection so we can execute the query.
statement = conn.createStatement();
statement.executeUpdate(sb.toString());
tablesCreated = true;
} catch (Exception e){
System.out.println(e.getMessage());
} finally {
if(statement != null){
try {
statement.close();
}
catch(Exception e){
System.err.println(e.getMessage());
System.exit(0); // Something is terribly wrong so just quit the program.
}
}
}
}
private void createAnimal (String animalName, String char1, String char2, String char3, String char4){
PreparedStatement pState = null;
try{
String sql = "Insert into Animal values (?,?,?,?,?,?)";
pState = conn.prepareStatement(sql);
pState.setInt(1, nextId);
pState.setString(2, animalName);
pState.setString(3, char1);
pState.setString(4, char2);
pState.setString(5, char3);
pState.setString(6, char3);
pState.executeUpdate();
pState.close();
incId();
}
catch (SQLException e){
System.err.println(e.getMessage());
}
}
private static void closeConnection() {
try {
// Close the connection
if(conn != null){
conn.close();
}
} catch(Exception e){
System.out.println(e.getMessage());
}
}
public static void queryShowAnimals() throws SQLException{
String query = "SELECT * FROM Animal";
try{
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(query);
while (rs.next()){
out.print(rs.getInt(nextId) + " ");
out.print(rs.getString("animalName") + " ");
out.print(rs.getString("char1") + ", ");
out.print(rs.getString("char2") + ", ");
out.print(rs.getString("char3") + ", ");
out.print(rs.getString("char4") + ", ");
}
}catch (SQLException se){}
}
public static void main(String[] args) throws ClassNotFoundException, SQLException {
AnimalDB1 db = new AnimalDB1();
AnimalDB1.createConnection();
System.out.println("Welcome to the Animal Database");
System.out.println("The list below shows all of the animals currently "
+ "stored in the database\n");
db.animalTable();
db.createAnimal("Huskie", "White", "Long hair", "Four legs", "Paws");
db.createAnimal("Salmon", "Silver", "Scales", "Fins", "Swims");
db.createAnimal("Crow", "Black", "Feathers", "Claws", "Flies");
db.createAnimal("Black Snake", "Black", "Scales", "No Appendages", "Slithers");
AnimalDB1.queryShowAnimals();
closeConnection();
}
}
【问题讨论】：