Develop Reference

Creating string by combining value from combobox and serial count

Right now my output of count is 0 for every element in combobox i.e it is like B10,B20,B30(B is the default value,next term is the value from database, and 0 is showing the count in this concatenated string)...my count is not increasing
What should I do so that my count increase when I select a value from Jcombobox
and press the button i.e.I get B10,B11,B12,B20,B21,B22,B30,B31,B32
public void actionPerformed(ActionEvent ae) {
String str = ae.getActionCommand();
if (str.equals("GENERATE PART NO. :")) {
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost/d03", "root", "");
st = con.createStatement();
String s = "select value from user1 where Userdata='" + jc.getSelectedItem() + "'";
rs = st.executeQuery(s);
t1.getText();
if (rs.next()) {
int j = 0;
String add1 = rs.getString("value");
t1.setEditable(false);
String str9 = new String();
str9 = "B" + add1; //B is the default value, add1 is the value from database
String str10 = new String();
str10 = str9 + j;
String query = "select MC from final";
ResultSet rs1 = st.executeQuery(query);
while (rs1.next()) {
if (str10.equals(rs1)) {
j = j + 1;
j=new Integer(j+1);
t1.setText(str10);
} else {
t1.setText(str10);
}
}
}
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost/d03", "root", "");
String s1 = ("insert into final(MC)values(?)");
PreparedStatement pstm = con.prepareStatement(s1);
pstm.setString(1, t1.getText());
int rowi = pstm.executeUpdate();
if (rowi > 0) {
JOptionPane.showMessageDialog(null, "DATA INSERTED");
}
} catch (Exception ex) {
ex.printStackTrace();
JOptionPane.showMessageDialog(null, "ERROR CLOSE");
}
}

The answer is quite simple:
Move str10 = str9 + j; into while body.
Your (fragment of the) code should look like:
/* if */while(rs.next()) {
int j = 0;
String add1 = rs.getString("value");
t1.setEditable(false);
// String str9; //= new String(); redundant
String str9 = "B" + add1; //B is the default value add1 is the value from database
String str10 = str9;
String query = "select MC from final";
ResultSet rs1 = st.executeQuery(query);
while (rs1.next()) {
if (str10.equals(rs1.getString("MC")) {
j++; //j = j + 1;
// j=new Integer(j+1); you simply increment j twice
str10 = str9 + j;// EDITED LINE!
}
t1.setText(str10);
}
}

Java sql Data pulling in the columnName but not the data

On this java method I am trying to get data from a ms-sql server. I am trying to get the int value from a column , Now the columns I am using are all int's but for some reason when i try pulling it as a INT I am getting a number format error saying that the column is a nvarchar. Not sure what is happening and when i ran the System.out I am noticing I am only pulling the column name but no data that the column has. Here is my method, I am not sure what I am doing wrong or what is missing from this. Any help will be greatly appreciated thank you.
private boolean CheckEmployee(long bDays) throws ClassNotFoundException, SQLException {
PreparedStatement preparedStatement;
String type = getTypeOfTimeOff().replaceAll("\\s+","");
Connection conn = null;
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
conn = DriverManager.getConnection(url, userName, password);
String selectProject = "SELECT ? FROM EmpVacationTbl Where FullName =? "
+ "AND ManagerName =?";
preparedStatement = conn.prepareStatement(selectProject);
preparedStatement.setString(1, getTypeOfTimeOff().replaceAll("\\s+",""));
preparedStatement.setString(2, getEmpName());
preparedStatement.setString(3, getManagerName());
System.out.println(preparedStatement.toString());
try (ResultSet rs = preparedStatement.executeQuery())
{
while (rs.next())
{
//int checker = rs.getInt(1);
String acheck = rs.getString(1);
System.out.println("TIME off the user has : " + acheck);
int checker = Integer.valueOf(acheck);
if(checker < bDays)
{
conn.close();
message = "Too many days";
return false;
}
else
{
conn.close();
return true;
}
}
if (rs.wasNull()) {
{
conn.close();
message = "Unable to find the days";
return false;
}
}
}
conn.close();
message = "Information not matching recordings.";
return false;
}

try {
stmt = con.createStatement();
ResultSet rs = stmt.executeQuery(query);
while (rs.next()) {
int aCheck = rs.getInt("column name");
}
}catch(){}
like this

For some reason what i did was add an AS to my query along with adding a if statement to my code caused the resultset to work with my code and allowed me to pull numbers from my database. Thank you for your help. Here is the updated code i added if it helps anyone.
private boolean CheckEmployee(long bDays) throws ClassNotFoundException, SQLException {
PreparedStatement preparedStatement;
Connection conn = null;
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
conn = DriverManager.getConnection(url, userName, password);
String selectProject = null;
if(getTypeOfTimeOff().equalsIgnoreCase("Vacation Day"))
selectProject = "SELECT VacationDay As dayList FROM EmpVacationTbl Where FullName =? "
+ "AND ManagerName =?";
else if(getTypeOfTimeOff().equalsIgnoreCase("Bonus Day"))
selectProject = "SELECT BonusDay As dayList FROM EmpVacationTbl Where FullName =? "
+ "AND ManagerName =?";
else if(getTypeOfTimeOff().equalsIgnoreCase("Birthday Day"))
selectProject = "SELECT BirthdayDay As dayList FROM EmpVacationTbl Where FullName =? "
+ "AND ManagerName =?";
System.out.println("Query String : " + selectProject);
preparedStatement = conn.prepareStatement(selectProject);
preparedStatement.setString(1, getEmpName());
preparedStatement.setString(2, getManagerName());
System.out.println(preparedStatement.toString());
try (ResultSet rs = preparedStatement.executeQuery())
{
while (rs.next())
{
int checker = 0 ;
checker = rs.getInt("dayList");
System.out.println("Days the user has off are: " + checker );
if(checker < bDays)
{
conn.close();
message = "Too many days";
return false;
}
else
{
conn.close();
return true;
}
}
if (rs.wasNull()) {
{
conn.close();
message = "Unable to find the days";
return false;
}
}
}
conn.close();
message = "Information not matching recordings.";
return false;
}

How to paint an image in Jtable with Mysql

Hello I would like to print data from mysql query to my Jtable, I knw how to print the conventional data(String), but do not know how to do it with pictures. What I need is print the picture in the first cell of the table.
public void SearchMovie() throws SQLException {
try {
Connection con = null;
ResultSet rs = null;
Statement st = null;
String Genre = ComboGenero.getSelectedItem().toString();
String Era = ComboEra.getSelectedItem().toString();
String Clsssification = ComboClasification.getSelectedItem().toString();
String sql = "select Foto,Title,Year,Country ,Rating from movie where Genre ='" + Genre + "'";
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost/whichmovie", "Asis", "dekrayat24");
st = con.createStatement();
rs = st.executeQuery(sql);
DefaultTableModel model = new DefaultTableModel();
this.jTable1.setModel(model);
jTable1.setDefaultRenderer(Object.class,new IconCellRenderer());
jTable1.setRowHeight(40);
ResultSetMetaData rsMD = rs.getMetaData();
int numcolumnas = rsMD.getColumnCount();
for (int x = 1; x <= numcolumnas; x++) {
model.addColumn(rsMD.getColumnLabel(x));
}
while (rs.next()) {
Object[] fila = new Object[numcolumnas];
for (int i = 0; i < numcolumnas; i++) {
fila[i] = rs.getObject(i + 1);
ResultadosLabel.setText(numcolumnas + "Movies found");
}
model.addRow(fila);
}
rs.close();
st.close();
con.close();
} catch (ClassNotFoundException ex) {
System.out.println(ex.getMessage());
}
}
Thanks .

Inserting records into a MySQL table using Java

I created a database with one table in MySQL:
CREATE DATABASE iac_enrollment_system;
USE iac_enrollment_system;
CREATE TABLE course(
course_code CHAR(7),
course_desc VARCHAR(255) NOT NULL,
course_chair VARCHAR(255),
PRIMARY KEY(course_code)
);
I tried to insert a record using Java:
// STEP 1: Import required packages
import java.sql.*;
import java.util.*;
public class SQLInsert {
// JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost:3306/iac_enrollment_system";
// Database credentials
static final String USER = "root";
static final String PASS = "1234";
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
Scanner scn = new Scanner(System.in);
String course_code = null, course_desc = null, course_chair = null;
try {
// STEP 2: Register JDBC driver
Class.forName("com.mysql.jdbc.Driver");
// STEP 3: Open a connection
System.out.print("\nConnecting to database...");
conn = DriverManager.getConnection(DB_URL, USER, PASS);
System.out.println(" SUCCESS!\n");
// STEP 4: Ask for user input
System.out.print("Enter course code: ");
course_code = scn.nextLine();
System.out.print("Enter course description: ");
course_desc = scn.nextLine();
System.out.print("Enter course chair: ");
course_chair = scn.nextLine();
// STEP 5: Excute query
System.out.print("\nInserting records into table...");
stmt = conn.createStatement();
String sql = "INSERT INTO course " +
"VALUES (course_code, course_desc, course_chair)";
stmt.executeUpdate(sql);
System.out.println(" SUCCESS!\n");
} catch(SQLException se) {
se.printStackTrace();
} catch(Exception e) {
e.printStackTrace();
} finally {
try {
if(stmt != null)
conn.close();
} catch(SQLException se) {
}
try {
if(conn != null)
conn.close();
} catch(SQLException se) {
se.printStackTrace();
}
}
System.out.println("Thank you for your patronage!");
}
}
The output appears to return successfully:
But when I select from MySQL, the inserted record is blank:
Why is it inserting a blank record?

no that cannot work(not with real data):
String sql = "INSERT INTO course " +
"VALUES (course_code, course_desc, course_chair)";
stmt.executeUpdate(sql);
change it to:
String sql = "INSERT INTO course (course_code, course_desc, course_chair)" +
"VALUES (?, ?, ?)";
Create a PreparedStatment with that sql and insert the values with index:
PreparedStatement preparedStatement = conn.prepareStatement(sql);
preparedStatement.setString(1, "Test");
preparedStatement.setString(2, "Test2");
preparedStatement.setString(3, "Test3");
preparedStatement.executeUpdate();

this can also be done like this if you don't want to use prepared statements.
String sql = "INSERT INTO course(course_code,course_desc,course_chair)"+"VALUES('"+course_code+"','"+course_desc+"','"+course_chair+"');"
Why it didnt insert value is because you were not providing values, but you were providing names of variables that you have used.

This should work for any table, instead of hard-coding the columns.
//Source details
String sourceUrl = "jdbc:oracle:thin:#//server:1521/db";
String sourceUserName = "src";
String sourcePassword = "***";
// Destination details
String destinationUserName = "dest";
String destinationPassword = "***";
String destinationUrl = "jdbc:mysql://server:3306/db";
Connection srcConnection = getSourceConnection(sourceUrl, sourceUserName, sourcePassword);
Connection destConnection = getDestinationConnection(destinationUrl, destinationUserName, destinationPassword);
PreparedStatement sourceStatement = srcConnection.prepareStatement("SELECT * FROM src_table ");
ResultSet rs = sourceStatement.executeQuery();
rs.setFetchSize(1000); // not needed
ResultSetMetaData meta = rs.getMetaData();
List<String> columns = new ArrayList<>();
for (int i = 1; i <= meta.getColumnCount(); i++)
columns.add(meta.getColumnName(i));
try (PreparedStatement destStatement = destConnection.prepareStatement(
"INSERT INTO dest_table ("
+ columns.stream().collect(Collectors.joining(", "))
+ ") VALUES ("
+ columns.stream().map(c -> "?").collect(Collectors.joining(", "))
+ ")"
)
)
{
int count = 0;
while (rs.next()) {
for (int i = 1; i <= meta.getColumnCount(); i++) {
destStatement.setObject(i, rs.getObject(i));
}
destStatement.addBatch();
count++;
}
destStatement.executeBatch(); // you will see all the rows in dest once this statement is executed
System.out.println("done " + count);
}

There is a mistake in your insert statement chage it to below and try :
String sql = "insert into table_name values ('" + Col1 +"','" + Col2 + "','" + Col3 + "')";

Retrieve column names from java.sql.ResultSet

With java.sql.ResultSet is there a way to get a column's name as a String by using the column's index? I had a look through the API doc but I can't find anything.

You can get this info from the ResultSet metadata. See ResultSetMetaData
e.g.
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
ResultSetMetaData rsmd = rs.getMetaData();
String name = rsmd.getColumnName(1);
and you can get the column name from there. If you do
select x as y from table
then rsmd.getColumnLabel() will get you the retrieved label name too.

In addition to the above answers, if you're working with a dynamic query and you want the column names but do not know how many columns there are, you can use the ResultSetMetaData object to get the number of columns first and then cycle through them.
Amending Brian's code:
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
// The column count starts from 1
for (int i = 1; i <= columnCount; i++ ) {
String name = rsmd.getColumnName(i);
// Do stuff with name
}

You can use the the ResultSetMetaData (http://java.sun.com/javase/6/docs/api/java/sql/ResultSetMetaData.html) object for that, like this:
ResultSet rs = stmt.executeQuery("SELECT * FROM table");
ResultSetMetaData rsmd = rs.getMetaData();
String firstColumnName = rsmd.getColumnName(1);

This question is old and so are the correct previous answers. But what I was looking for when I found this topic was something like this solution. Hopefully it helps someone.
// Loading required libraries
import java.util.*;
import java.sql.*;
public class MySQLExample {
public void run(String sql) {
// JDBC driver name and database URL
String JDBC_DRIVER = "com.mysql.jdbc.Driver";
String DB_URL = "jdbc:mysql://localhost/demo";
// Database credentials
String USER = "someuser"; // Fake of course.
String PASS = "somepass"; // This too!
Statement stmt = null;
ResultSet rs = null;
Connection conn = null;
Vector<String> columnNames = new Vector<String>();
try {
// Register JDBC driver
Class.forName(JDBC_DRIVER);
// Open a connection
conn = DriverManager.getConnection(DB_URL, USER, PASS);
// Execute SQL query
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
if (rs != null) {
ResultSetMetaData columns = rs.getMetaData();
int i = 0;
while (i < columns.getColumnCount()) {
i++;
System.out.print(columns.getColumnName(i) + "\t");
columnNames.add(columns.getColumnName(i));
}
System.out.print("\n");
while (rs.next()) {
for (i = 0; i < columnNames.size(); i++) {
System.out.print(rs.getString(columnNames.get(i))
+ "\t");
}
System.out.print("\n");
}
}
} catch (Exception e) {
System.out.println("Exception: " + e.toString());
}
finally {
try {
if (rs != null) {
rs.close();
}
if (stmt != null) {
stmt.close();
}
if (conn != null) {
conn.close();
}
} catch (Exception mysqlEx) {
System.out.println(mysqlEx.toString());
}
}
}
}

SQLite 3
Using getMetaData();
DatabaseMetaData md = conn.getMetaData();
ResultSet rset = md.getColumns(null, null, "your_table_name", null);
System.out.println("your_table_name");
while (rset.next())
{
System.out.println("\t" + rset.getString(4));
}
EDIT: This works with PostgreSQL as well

import java.sql.*;
public class JdbcGetColumnNames {
public static void main(String args[]) {
Connection con = null;
Statement st = null;
ResultSet rs = null;
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/komal", "root", "root");
st = con.createStatement();
String sql = "select * from person";
rs = st.executeQuery(sql);
ResultSetMetaData metaData = rs.getMetaData();
int rowCount = metaData.getColumnCount();
System.out.println("Table Name : " + metaData.getTableName(2));
System.out.println("Field \tDataType");
for (int i = 0; i < rowCount; i++) {
System.out.print(metaData.getColumnName(i + 1) + " \t");
System.out.println(metaData.getColumnTypeName(i + 1));
}
} catch (Exception e) {
System.out.println(e);
}
}
}
Table Name : person
Field DataType
id VARCHAR
cname VARCHAR
dob DATE

while (rs.next()) {
for (int j = 1; j < columncount; j++) {
System.out.println( rsd.getColumnName(j) + "::" + rs.getString(j));
}
}

When you need the column names, but do not want to grab entries:
PreparedStatement stmt = connection.prepareStatement("SHOW COLUMNS FROM `yourTable`");
ResultSet set = stmt.executeQuery();
//store all of the columns names
List<String> names = new ArrayList<>();
while (set.next()) { names.add(set.getString("Field")); }
NOTE: Only works with MySQL

The SQL statements that read data from a database query return the data in a result set. The SELECT statement is the standard way to select rows from a database and view them in a result set. The **java.sql.ResultSet** interface represents the result set of a database query.
Get methods: used to view the data in the columns of the current row
being pointed to by the cursor.
Using MetaData of a result set to fetch the exact column count
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
ResultSetMetaData rsmd = rs.getMetaData();
int numberOfColumns = rsmd.getColumnCount();
boolean b = rsmd.isSearchable(1);
http://docs.oracle.com/javase/7/docs/api/java/sql/ResultSetMetaData.html
and further more to bind it to data model table
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
try {
//STEP 2: Register JDBC driver
Class.forName("com.mysql.jdbc.Driver");
//STEP 3: Open a connection
System.out.println("Connecting to a selected database...");
conn = DriverManager.getConnection(DB_URL, USER, PASS);
System.out.println("Connected database successfully...");
//STEP 4: Execute a query
System.out.println("Creating statement...");
stmt = conn.createStatement();
String sql = "SELECT id, first, last, age FROM Registration";
ResultSet rs = stmt.executeQuery(sql);
//STEP 5: Extract data from result set
while(rs.next()){
//Retrieve by column name
int id = rs.getInt("id");
int age = rs.getInt("age");
String first = rs.getString("first");
String last = rs.getString("last");
//Display values
System.out.print("ID: " + id);
System.out.print(", Age: " + age);
System.out.print(", First: " + first);
System.out.println(", Last: " + last);
}
rs.close();
} catch(SQLException se) {
//Handle errors for JDBC
se.printStackTrace();
} catch(Exception e) {
//Handle errors for Class.forName
e.printStackTrace();
} finally {
//finally block used to close resources
try {
if(stmt!=null)
conn.close();
} catch(SQLException se) {
} // do nothing
try {
if(conn!=null)
conn.close();
} catch(SQLException se) {
se.printStackTrace();
} //end finally try
}//end try
System.out.println("Goodbye!");
}//end main
//end JDBCExample
very nice tutorial here : http://www.tutorialspoint.com/jdbc/
ResultSetMetaData meta = resultset.getMetaData(); // for a valid resultset object after executing query
Integer columncount = meta.getColumnCount();
int count = 1 ; // start counting from 1 always
String[] columnNames = null;
while(columncount <=count) {
columnNames [i] = meta.getColumnName(i);
}
System.out.println (columnNames.size() ); //see the list and bind it to TableModel object. the to your jtbale.setModel(your_table_model);

#Cyntech is right.
Incase your table is empty and you still need to get table column names you can get your column as type Vector,see the following:
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
Vector<Vector<String>>tableVector = new Vector<Vector<String>>();
boolean isTableEmpty = true;
int col = 0;
while(rs.next())
{
isTableEmpty = false; //set to false since rs.next has data: this means the table is not empty
if(col != columnCount)
{
for(int x = 1;x <= columnCount;x++){
Vector<String> tFields = new Vector<String>();
tFields.add(rsmd.getColumnName(x).toString());
tableVector.add(tFields);
}
col = columnCount;
}
}
//if table is empty then get column names only
if(isTableEmpty){
for(int x=1;x<=colCount;x++){
Vector<String> tFields = new Vector<String>();
tFields.add(rsmd.getColumnName(x).toString());
tableVector.add(tFields);
}
}
rs.close();
stmt.close();
return tableVector;

ResultSet rsTst = hiSession.connection().prepareStatement(queryStr).executeQuery();
ResultSetMetaData meta = rsTst.getMetaData();
int columnCount = meta.getColumnCount();
// The column count starts from 1
String nameValuePair = "";
while (rsTst.next()) {
for (int i = 1; i < columnCount + 1; i++ ) {
String name = meta.getColumnName(i);
// Do stuff with name
String value = rsTst.getString(i); //.getObject(1);
nameValuePair = nameValuePair + name + "=" +value + ",";
//nameValuePair = nameValuePair + ", ";
}
nameValuePair = nameValuePair+"||" + "\t";
}

If you want to use spring jdbctemplate and don't want to deal with connection staff, you can use following:
jdbcTemplate.query("select * from books", new RowCallbackHandler() {
public void processRow(ResultSet resultSet) throws SQLException {
ResultSetMetaData rsmd = resultSet.getMetaData();
for (int i = 1; i <= rsmd.getColumnCount(); i++ ) {
String name = rsmd.getColumnName(i);
// Do stuff with name
}
}
});

U can get column name and value from resultSet.getMetaData();
This code work for me:
Connection conn = null;
PreparedStatement preparedStatement = null;
try {
Class.forName("com.mysql.cj.jdbc.Driver");
conn = MySQLJDBCUtil.getConnection();
preparedStatement = conn.prepareStatement(sql);
if (params != null) {
for (int i = 0; i < params.size(); i++) {
preparedStatement.setObject(i + 1, params.get(i).getSqlValue());
}
ResultSet resultSet = preparedStatement.executeQuery();
ResultSetMetaData md = resultSet.getMetaData();
while (resultSet.next()) {
int counter = md.getColumnCount();
String colName[] = new String[counter];
Map<String, Object> field = new HashMap<>();
for (int loop = 1; loop <= counter; loop++) {
int index = loop - 1;
colName[index] = md.getColumnLabel(loop);
field.put(colName[index], resultSet.getObject(colName[index]));
}
rows.add(field);
}
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (preparedStatement != null) {
try {
preparedStatement.close();
}catch (Exception e1) {
e1.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
return rows;

I know, this question is already answered but probably somebody like me needs to access a column name from DatabaseMetaData by label instead of index:
ResultSet resultSet = null;
DatabaseMetaData metaData = null;
try {
metaData = connection.getMetaData();
resultSet = metaData.getColumns(null, null, tableName, null);
while (resultSet.next()){
String name = resultSet.getString("COLUMN_NAME");
}
}