Please give me an idea how to execute statement to DB.
There are 2 tables(sorry for incorrect writing - it is just to give information about columns):
contractors(contractor_id, contractor_name, contract_num)
invoices(contractor_id, invoice_num, invoice_date, invoice_amount)
The 'contractor_id' in 'invoices' is a foreign key for 'contractor_id' in 'contractors'. How to insert in 'invoices'-table the following data: invoice_num, invoice_date, invoice_amount, if I have the 'contractor_name' from 'contractors'-table?
The solution which works is:
public void insertInvoiceDataByContractorName(String contractorsName, String invoiceNum, String date, float amount) {
String contrId = null;
try {
preparedStatement = connection.prepareStatement("SELECT contractor_id FROM contractors WHERE contractor_name=?");
preparedStatement.setString(1, contractorsName);
resultSet = preparedStatement.executeQuery();
while (resultSet.next()) {
contrId = resultSet.getString(1);
}
preparedStatement = connection.prepareStatement("INSERT INTO invoices VALUES(?, ?, ? ,?)");
preparedStatement.setString(1, contrId);
preparedStatement.setString(2, invoiceNum);
preparedStatement.setString(3, date);
preparedStatement.setFloat(4, amount);
preparedStatement.execute();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (preparedStatement != null) {preparedStatement.close();}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
I don't know how to make it correct and more simpler by using just one statement. Thank you in advance for pieces of advice.
Use
INSERT INTO invoices SELECT contractor_id, ?, ?, ? FROM contractors WHERE contractor_name=?
this will insert 1 row assuming your contractor name is unique
Related
Two tables are present in the database, one is Student table with columns roll_no(PK), name, grade and DOB, another table StudentLeft with columns roll_no, name, grade and leaving_date.
I want to delete the record of the student from Student table whose roll no is entered by the user, and add the roll no, name, grade and leaving_date (the date when the record is deleted and added to the table) to StudentLeft table.
This is my method.
public static void main(String[] args) throws SQLException {
Connection connection = null;
PreparedStatement preparedStatement = null, preparedStatement1 = null, preparedStatement2 = null;
ResultSet resultSet = null;
String selectQuery = "", updateQuery = "", deleteQuery = "";
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
connection = dataSource.getConnection();
}
catch (ClassNotFoundException e) {
e.printStackTrace();
}
catch (SQLException e) {
e.printStackTrace();
}
int rollNo = Integer.parseInt(args[0]);
try {
selectQuery = "SELECT name, grade FROM Student WHERE roll_no = ?";
updateQuery = "INSERT INTO StudentLog values WHERE roll_no = ?, name = ?, standard = ?";
deleteQuery = "DELETE Student WHERE roll_no = ?";
connection.setAutoCommit(false);
preparedStatement = connection.prepareStatement(selectQuery);
preparedStatement.setInt(1, rollNo);
resultSet = preparedStatement.executeQuery();
preparedStatement1 = connection.prepareStatement(updateQuery);
preparedStatement1.setInt(1, rollNo);
while (resultSet.next()) {
String name = resultSet.getString("name");
String grade = resultSet.getString("grade");
preparedStatement1.setString(2, name);
preparedStatement1.setString(3, grade);
preparedStatement1.addBatch();
}
preparedStatement1.executeBatch();
preparedStatement2 = connection.prepareStatement(deleteQuery);
preparedStatement.setInt(1, rollNo);
connection.commit();
}
catch (SQLException e) {
e.printStackTrace();
}
try {
if (!preparedStatement.isClosed() || !preparedStatement1.isClosed() || !preparedStatement2.isClosed()) {
preparedStatement.close();
preparedStatement1.close();
preparedStatement2.close();
}
if (!connection.isClosed())
connection.close();
}
catch (SQLException e) {
e.printStackTrace();
}
}
These are the errors.
java.sql.BatchUpdateException: ORA-00936: missing expression
at oracle.jdbc.driver.OraclePreparedStatement.executeBatch(OraclePreparedStatement.java:10500)
at oracle.jdbc.driver.OracleStatementWrapper.executeBatch(OracleStatementWrapper.java:230)
at Q3.main(Q3.java:48)
Exception in thread "main" java.lang.NullPointerException
at Q3.main(Q3.java:62)
I am using oracle 11g express database.
The code you've written can be simplified quite a bit:
public static void main(String[] args) {
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
}
catch (ClassNotFoundException e) {
e.printStackTrace();
return;
}
int rollNo = Integer.parseInt(args[0]);
try (Connection connection = dataSource.getConnection()) {
connection.setAutoCommit(false);
String transferStatement = "INSERT INTO StudentLog (roll_no, name, standard, leaving_date) " +
"SELECT roll_no, name, standard, SYSDATE FROM Student WHERE roll_no = ?";
try (PreparedStatement stmt = connection.prepareStatement(transferStatement)) {
stmt.setInt(1, rollNo);
stmt.executeUpdate();
}
String deleteStatement = "DELETE FROM Student WHERE roll_no = ?";
try (PreparedStatement stmt = connection.prepareStatement(deleteStatement)) {
stmt.setInt(1, rollNo);
stmt.executeUpdate();
}
connection.commit();
}
catch (SQLException e) {
e.printStackTrace();
}
}
I've used try-with-resources statements, which simplifies the clean-up of connections and prepared statements: the connection and statements will get closed when the code inside the try (...) block finishes executing.
Transferring data from the Student table to the StudentLog table can be done in one go with an INSERT INTO ... SELECT statement. This statement doesn't return any result set: there's nothing to iterate through, we just execute it and the row gets inserted.
The DELETE statement is similar: it too returns no result set. I've added the keyword FROM to it out of convention more than anything else: as pointed out on another answer, FROM is optional.
I've also moved the catch (SQLException e) block to the end: that will handle all SQLExceptions generated when connecting to the database or executing either of the prepared statements.
I've kept the code that attempts to load the Oracle database driver class, but added a return statement in the catch block: if there's an exception, the driver isn't on the classpath and connecting to the database is guaranteed to fail so we may as well stop. However, for recent versions of the Oracle driver you don't need this check. Experiment with it: see if the code works without this check and if so, remove it.
Shouldn't your query be
DELETE FROM Student WHERE roll_no = ?
instead of
DELETE Student WHERE roll_no = ?
Your DELETE code used the wrong prepared statement, missing an execute.
It is advisable to use try-with-resources as below, for the automatic closing,
even on return or exception. (It also takes care of variable scopes.)
public static void main(String[] args) throws SQLException {
int rollNo = Integer.parseInt(args[0]);
// Better statements possible.
final String selectQuery = "SELECT name, grade FROM Student WHERE roll_no = ?";
final String updateQuery =
"INSERT INTO StudentLog VALUES WHERE roll_no = ?, name = ?, standard = ?";
final String deleteQuery = "DELETE FROM Student WHERE roll_no = ?";
try { // Check whether you need this. It is for the old discovery mechanism.
Class.forName("oracle.jdbc.driver.OracleDriver");
}
catch (ClassNotFoundException e) {
throw new IllegalStateException("Database driver not provided", e);
}
try (Connection connection = dataSource.getConnection()) {
connection.setAutoCommit(false);
try (PreparedStatement preparedStatement =
connection.prepareStatement(selectQuery)) {
preparedStatement.setInt(1, rollNo);
try (ResultSet resultSet = preparedStatement.executeQuery()) {
try (PreparedStatement preparedStatement1 =
connection.prepareStatement(updateQuery)) {
preparedStatement1.setInt(1, rollNo);
while (resultSet.next()) {
String name = resultSet.getString("name");
String grade = resultSet.getString("grade");
preparedStatement1.setString(2, name);
preparedStatement1.setString(3, grade);
preparedStatement1.addBatch();
}
preparedStatement1.executeBatch();
}
}
}
try (PreparedStatement preparedStatement2 =
connection.prepareStatement(deleteQuery)) {
preparedStatement2.setInt(1, rollNo); // NOT preparedStatement
preparedStatement2.executeUpdate();
}
connection.commit();
}
}
Then one should SELECT+INSERT to the database, using one statement (INSERT SELECT).
The SQL of the StudentLog is a bit incomprehensible to me, but a nice INSERT would be:
INSERT INTO StudentLog VALUES(roll_no, name, standard)
SELECT roll_no, name, grade
FROM Student
WHERE roll_no = ?
Removing the need java nesting of database accesses.
I am writing the code for a sign-up page for a system. Once the button is clicked, the system will check if the user is above the age of 14. If true, the system should save all the inputted data into a SQL Database.
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
int age = Integer.parseInt(Age_Input.getText());
String firstname = FirstName_Input.getText();
String surname = Surname_Input.getText();
String email = Email_Input.getText();
String userid = UserID_InputSignUp.getText();
char[] pass = Password_InputSignUp.getPassword();
if (age<14) {
JOptionPane.showMessageDialog(null,"Sorry, You need to be at least 14 years to use this software... ");
new Login_Page().setVisible(true);
this.setVisible(false);
} else {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
Connection connect = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/user_info", "root", "nerdswonka");
Statement stmt = connect.createStatement();
String query1 = "INSERT INTO user_info(user_id, password, firstname, lastname, emailid, age) VALUES('"+userid+"', "+Arrays.toString(pass)+", '"+firstname+"', '"+surname+"', '"+email+"', "+age+");";
stmt.executeUpdate(query1);
JOptionPane.showMessageDialog(null, "Account Creation succesful!");
stmt.close();
connect.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "Error in connecting to SQL Database");
}
new Login_Page().setVisible(true);
this.setVisible(false);
}
}
The code isn't updating anything into the database and is simply showing JOptionPane after an exception (error ) comes. What edits can be done to the code so that values get stored into SQL?
The immediate cause of the failure is probably that your INSERT statement contains the following string which is not being single quoted:
Arrays.toString(pass)
However, you should completely abandon your current approach and instead use a prepared statement:
String sql = "INSERT INTO user_info (user_id, password, firstname, lastname, emailid, age) " +
"VALUES (?, ?, ?, ?, ?, ?)";
try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/user_info", "root", "nerdswonka");
PreparedStatement ps = conn.prepareStatement(sql)) {
ps.setString(1, userid);
ps.setString(2, Arrays.toString(pass));
ps.setString(3, firstname);
ps.setString(4, surname);
ps.setString(5, email);
ps.setInt(6, age);
int row = ps.executeUpdate();
System.out.println(row); // rows inserted (should be 1)
}
catch (SQLException e) {
System.err.format("SQL State: %s\n%s", e.getSQLState(), e.getMessage());
}
catch (Exception e) {
e.printStackTrace();
}
}
Prepared statements do many things, one of which is handling the messy details about how to properly escape your literal data in a SQL query. In this case, they free you from having to worry about placing single quotes around your interpolated Java strings. Statements also prevent bad things like SQL injection from happening.
You are not printing your exception in catch block. You can use e.printStackTrace(); to print exception first.
I get an sql error when trying to insert something into my DB.
I give a bunch of input to my method, convert that input into strings or sql time and want to store it.
public static void setCourseList(String courseDescription, String courseName, LocalTime courseStart, LocalTime courseEnd, LocalDate courseDate, DayOfWeek courseDay) {
Connection conn = null;
try {
// db parameters
// path to db relative to run time directory
String url = "jdbc:sqlite:Holiday.db";
String sqlInsertCourse = "INSERT INTO COURSE (Name,Start,End,Date,Day,Description) VALUES (?, ?,?, ?,?, ?,);";
conn = DriverManager.getConnection(url);
System.out.println("Connected");
Statement stmt = conn.createStatement();
PreparedStatement pstmt = conn.prepareStatement(sqlInsertCourse);
pstmt.setString(1, courseName);
String courseStartString = courseStart.toString();
pstmt.setString(2, courseStartString);
java.sql.Time courseEndTime = Time.valueOf(courseEnd);
pstmt.setTime(3, courseEndTime);
java.sql.Date courseDateDate = java.sql.Date.valueOf(courseDate);
pstmt.setDate(4, courseDateDate);
String courseDayString = courseDay.toString();
pstmt.setString(5, courseDayString);
pstmt.executeUpdate();
pstmt.close();
System.out.println("Connection to SQLite has been established.");
// create tables if they do not exists
stmt.execute(sqlInsertCourse);
} catch (SQLException e) {
System.out.println(e.getMessage());
} finally {
try {
if (conn != null) {
conn.close();
}
} catch (SQLException ex) {
System.out.println(ex.getMessage());
}
}
}
I would expect it to store the input in my db.
I do get an [SQLITE_ERROR] SQL error or missing database (near ")": syntax error) error instead.
Any help is appreciated.
I am new to sql.
Change
String sqlInsertCourse = "INSERT INTO COURSE (Name,Start,End,Date,Day,Description) VALUES (?, ?,?, ?,?, ?,);";
To
String sqlInsertCourse = "INSERT INTO COURSE (Name,Start,End,Date,Day,Description) VALUES (?, ?,?, ?,?, ?);"; //<<<<<<<<<< extra comma removed
As per the comment on the line the final comma after the last ? has been removed.
Same as what Mike has answered, you can change it to
String sqlInsertCourse = "INSERT INTO COURSE (Name,Start,End,Date,Day,Description) VALUES (""put values here"");";
If you are wondering why it doesn't throw you an error, it's because there is no syntax error in the java, there's an error in the SQL which only the database can throw, but you're computer can't recognize. Hope this answers your question.
Can't seem to fix this. Been trying to get it to work for the past hour. any help would be appreciated.
INFO: Server startup in 868 ms
java.sql.SQLException: Can not issue data manipulation statements with executeQuery().Event{id=0, name='dads', venue='dasd', startDate='11/11/11', endDate='12/11/11'}
Seemed to be getting an error when I try to do an insert.
public void addEvent(Event event) throws DaoException{
Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
con = this.getConnection();
String query = "INSERT INTO TABLE EVENT VALUES(null, ?, ?, ?, ?)";
ps = con.prepareStatement(query);
ps.setString(1, event.getName());
ps.setString(2, event.getVenue());
ps.setString(3, event.getStartDate());
ps.setString(4, event.getEndDate());
rs = ps.executeQuery();
}catch(SQLException e) {
System.out.println(event.toString());
e.printStackTrace();
}finally {
try {
if (rs != null) {
rs.close();
}
if (ps != null) {
ps.close();
}
if (con != null) {
freeConnection(con);
}
} catch (SQLException e) {
throw new DaoException("Couldn't " + e.getMessage());
}
}
}
for inserting or updating or deleting you should use executeUpdate()
executeUpdate() returns int value
so replace this line rs = ps.executeQuery(); with
int result = ps.executeUpdate();
Note you will get another error after modifying as per above because you sql query is also wrong
Use the following query
INSERT INTO EVENT VALUES(null, ?, ?, ?, ?)
it looks like incorrect syntax of INSERT Query, update it likewise
INSERT INTO EVENT VALUES(null, ?, ?, ?, ?) // remove TABLE word
//INSERT INTO TABLE_NAME VALUES(...) , this is correct syntax.
also correct here too
executeUpdate() instead of executeQuery()
// for insert/update/delete query always use executeUpdate(),
// for select query use executeQuery()
I tried to save / edit / delete a new row in the database. writing in the gui values to be saved with getText ()
here is the code
Connection conn = Connessione.ConnecrDb();
Statement stmt = null;
ResultSet emps = null;
try{
String sql;
sql = "INSERT INTO PROGETTO.LIBRO (ISBN, DISPONIBILITA, TITOLO, CASA_EDITRICE, CODICE_AUTORE, GENERE, PREZZO)"
+ "VALUES (txt_isbn, txt_disp, txt_titolo, txt_casa, txt_autore, txt_genere, txt_prezzo)";
stmt = conn.createStatement();
emps = stmt.executeQuery(sql);
String ISBN= txt_isbn.getText();
String DISPONIBILITA= txt_disp.getText();
String TITOLO= txt_titolo.getText();
String CASA_EDITRICE= txt_casa.getText();
String CODICE_AUTORE= txt_autore.getText();
String GENERE= txt_genere.getText();
String PREZZO = txt_prezzo.getText();
JOptionPane.showMessageDialog(null, "SALVATO");
}catch(SQLException | HeadlessException e)
{
JOptionPane.showMessageDialog(null, e);
}
finally
{
try{
if (emps != null)
emps.close();
}
catch (SQLException e) { }
try
{
if (stmt != null)
stmt.close();
}
catch (SQLException e) { }
}
Getting this error: column not allowed here
Above code just takes care of insert operation. How can I delete and modify table record?
You have asked 2 different questions here
1. Column not allowed here
This happened because you have not passed values for any of parameter into insert statement.
I am not sure about your requirement however I will use PreparedStatement for this scenario.
Example
String insertTableSQL = "INSERT INTO DBUSER"
+ "(USER_ID, USERNAME, CREATED_BY, CREATED_DATE) VALUES"
+ "(?,?,?,?)";
PreparedStatement preparedStatement = dbConnection.prepareStatement(insertTableSQL);
preparedStatement.setInt(1, 11);
preparedStatement.setString(2, "MindPeace");
preparedStatement.setString(3, "system");
preparedStatement.setTimestamp(4, getCurrentTimeStamp());
preparedStatement .executeUpdate();
2. This code is only to save the data, delete, and modify an entire row how can I do?
Answer is very simple. You have to write code for the same :)
You need 3 SQL statement which has DELETE and UPDATE operation just like insert in above example.
String sql = "INSERT INTO PROGETTO.LIBRO (ISBN, DISPONIBILITA, TITOLO, "
+ "CASA_EDITRICE, CODICE_AUTORE, GENERE, PREZZO)"
+ "VALUES (?, ?, ?, ?, ?, ?, ?)";
try (PreparedStatement stmt = conn.createStatement()) {
NumberFormat numberFormat = NumberFormat.getInstance(Locale.ITALY);
String ISBN = txt_isbn.getText();
String DISPONIBILITA = txt_disp.getText();
String TITOLO = txt_titolo.getText();
String CASA_EDITRICE = txt_casa.getText();
String CODICE_AUTORE = txt_autore.getText();
String GENERE = txt_genere.getText();
BigDecimal PREZZO = new BigDecimal(
numberFormat.parse(txt_prezzo.getText()).doubleValue())
.setScale(2);
stmt.setString(1, ISBN);
stmt.setString(2, DISPONIBILITA);
stmt.setString(3, TITOLO);
stmt.setString(4, CASA_EDITRICE);
stmt.setString(5, CODICE_AUTORE);
stmt.setString(6, GENERE);
stmt.setBigDecimal(7, PREZZO);
int updateCount = stmt.executeUpdate();
JOptionPane.showMessageDialog(null, "SALVATO");
} catch(SQLException | HeadlessException e) {
JOptionPane.showMessageDialog(null, e);
}
Try-with-resources closes the stmt automatically.
The prepared statement replaces the value in the SQL with something like:
INSERT INTO table(column1, colum2, ....)
VALUES('De\'l Rey',
1234.50,
...)
for:
"De'l Rey"
1.234,50
updateCount should be 1 on success.
Wooow..true!!
I created three buttons to delete / update / insert and now it all works and automatically updates the tables.
you've been very very great. Thank you very much.
one last thing.
if I wanted to insert an error message when I delete / update etc "book not found" I tried to create an if:
Boolean found = false;
try{
sql= delete......
etc
if (!found)
JOptionPane.showMessageDialog(null, "NOT FOUND","ERRORE",JOptionPane.WARNING_MESSAGE);
etc...
Connection conn = Connessione.ConnecrDb();
Statement stmt = null;
ResultSet emps = null;
try{
String sql= "DELETE FROM progetto.libro WHERE isbn =?"; /
pst=(OraclePreparedStatement) conn.prepareStatement(sql);
pst.setString (1, txt_isbn.getText());
pst.execute();
JOptionPane.showMessageDialog(null, "ELIMINATO");
Update_table();
txt_isbn.setText("");
txt_disp.setText("");
txt_titolo.setText("");
txt_casa.setText("");
txt_autore.setText("");
txt_genere.setText("");
txt_prezzo.setText("");
}
catch (Exception e)
{
JOptionPane.showMessageDialog(null,e);
}
if you find the book must exit the book removed, or "not found". but as I deployed I always come out "deleted". why?
thanks again