Develop Reference

How can you get a JTextField to work in a SQLite Select statement?

I am working on a program which will when finished allow the end user to keep track of there sound packs in a database through SQLite. The newest problem I am running into is that I can not get the Select statement to take a JTextField input. The reason that I want to do this is that I already have the text fields linked through the insert method. I have tried switching the variable types in the readAllData method and I am not entirely sure what other way to fix it.
The fields are as follows
PackId
PackName
VendorName
PackValue
what I want to happen is when I hit the Update button I want the data in the database to print out to the console (for now) and I am also going to be adding a select specified records method as well.
Here is the code I do apologize in advance this is a very long project:
public void readAllData() throws SQLException {
Connection conn = DriverManager.getConnection("jdbc:sqlite:packsver3.db");
PreparedStatement ps = null;
ResultSet rs = null;
try {
String sql = "SELECT * FROM packs";
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while(rs.next()) {
String PackId = PackId.getText();
String PackName = PackName.getText();
String VendorName = VendorName.getTextField();
String PackValue = rs.getTextField;
System.out.println("All Packs\n");
System.out.println("PackId: " +PackId);
System.out.println("PackName: " +PackName);
System.out.println("VendorName: " +VendorName);
System.out.println("PackValue: " +PackValue+"\n\n");
}
} catch (SQLException e) {
System.out.println(e.toString());
}finally {
try {
assert rs != null;
rs.close();
ps.close();
conn.close();
} catch (SQLException e) {
System.out.println(e.toString());
}
Console Output

Why does my for loop in android studio stop after the first iteration?

I created a system in which I can run all my postgre sql queries with only one single Async Task Class in Android Studio. This was really(!!) challenging due to the big amount of limitations that I had to face. But this works actually really great!
//Used for connecting to database and executing queries.
//Index 0 of input string must be the query, Index 1 must be the tablename we demand
//We can only gather data from 1 table for each query, so if you need data from several tablecolumns, use multiple queries like:
//[0] = query, [1] = tablename, [2] = 2nd query, [3] = 2nd tablename, [4] = 3rd query, [5] = 3rd table name ... and so on (each query must come with a tablename)
public class DBHandler extends AsyncTask<String, Void, List<String>>
{
public AsyncResponse delegate;
#Override
protected List<String> doInBackground(String...query)
{
List<String> result = new ArrayList<String>();
String sql;
String tableresult = null;
Connection conn = null;
Statement st = null;
ResultSet rs = null;
try {
Class.forName("org.postgresql.Driver");
conn = DriverManager.getConnection("jdbc:postgresql://192.168.200.300:5439/dbname?user=anonymous&password=secretpw");
st = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE); //necessary if you want to use rs.first() after rs.next(), it makes the resultset scrollable
for (int i = 0; i <= query.length-1; i = i+2) //queries are always stored in i=0 and/or in i+2, because i+1 contain the demanded tablenames for resultset handling
{
System.out.println("I is: " +i);
if (!query[i].isEmpty())
{
System.out.println(query[i]);
sql = query[i];
rs = st.executeQuery(sql);
while (rs.next())
if (!query[i + 1].isEmpty() || !rs.getString(query[i + 1]).isEmpty()) //if i+1 is empty, there is no demanded tablename. Used when we dont need any return values (ie. INSERT, UPDATE)
result.add(rs.getString(query[i + 1])); //demanded tablename is always stored in i+1
//We add an empty entry if we demand multiple tablenames so we can keep them seperate
//Might be replaced with any other char, but you will have to backtrack all usages of DBHandler and fix the filters there
if(i+2 < query.length)
result.add(" ");
}
rs.first(); //reset pointer for rs.next()
}
rs.close();
st.close();
conn.close();
System.out.println("End of AsyncTask");
}
catch (SQLException ex)
{
ex.printStackTrace();
}
catch (Exception e)
{
e.printStackTrace();
}
return result;
}
//onPostExecute returns query result in a List.
//We need to use interaces delegate feature to send the result to other classes, like "Auslieferung", which is implementing the interface
#Override
protected void onPostExecute(List<String> result)
{
super.onPostExecute(result);
System.out.println("Result: " +result.toString());
if (!result.isEmpty())
delegate.processFinish(result);
}
}
There is a for-loop in this Async Task.
for (int i = 0; i <= query.length-1; i = i+2)
And now finally I can explain my issue:
I usually use SELECT queries, sometimes I use an INSERT query (which can be done by a single query), but when I parse an Update Query, my for-loop stops iterating after the first pass, so i+2 never happens. The update queries look like this:
String updatequeries[] = {UPDATE delivery SET contactperson = 'Jon Doe' WHERE officeid = 5, " ", UPDATE delivery SET contactemail = 'abd#def.gh' WHERE officeid = 5, " "};
Why does this for loop stop running right after the first run? The debugger does not show anything unusual, everything was parsed right and there are no queries missing. Updating a table does not return any results, but nothing depends on result values here. I tried to run 20 update queries in a single string var, but the for loop stops after the first iteration anyway. No issues are displayed in the debugger or in the logs. Have I overseen something or is there anything I don't know? Might this be a bug? Please help me! This issue drives me crazy.

JDBC ResultSet closed in Java after several iterations

I am having a problem with a ResultSet being closed. What confuses me is that it works for a portion of the data and then closes. At first I thought it might be because of connection timeout but that doesn't seem the case.
This portion of the program pertains to comparing an .xlsx workbook to an already present SQL database and for lack of a better term merges/updates it.
First, in my CompareDatabase class I am calling a search function that searches an SQLite database for a specific string every 6 iterations.
int columnCount = 6;
dataPoint = dataPoint.replaceAll("Detail", "");
String[] temp = dataPoint.trim().split("\\s+");
System.out.println(Arrays.toString(temp));
for (String tempDataPoint : temp) {
if ( columnCount == 6) {
System.out.println(search(tempDataPoint, connection));
}
columnCount = 0;
} else {
columnCount++;
}
}
This search function (also in the CompareDatabase class is then supposed to search for the value and return a String (was originally a Boolean but I wanted to see the output).
private String search (String searchValue, Connection connection) throws SQLException {
PreparedStatement pStatement = null;
pStatement = connection.prepareStatement("SELECT * FROM lotdatabase where (Vehicle) = (?)");
pStatement.setString(1, searchValue);
try (ResultSet resultSet = pStatement.executeQuery()){
return resultSet.getString(1);
}finally {
close(pStatement);
}
}
At the end you can see that the PreparedStatement is closed. The ResultSet should also be closed automatically (I read somewhere) but JDBC could possibly be being unreliable.
The Connection however is still open as it will be searching some 200+ strings and opening and closing that many times did not seem like a good idea.
These functions are called by my main class here:
One is commented out since it will error out because of primary key violation.
public static void main(String[] args) {
SQLDatabase sqlDatabase = new SQLDatabase();
//sqlDatabase.convertToSQL("Database1.xlsx");
sqlDatabase.compare("Database2.xlsx");
}
I have a suspicion that I am going about a bunch of this wrong (on the aspect of managing connections an such) and I would appreciate a reference to where I can learn to do it properly.
Also, being that PreparedStatement can only handle one ResultSet I don't see that being my issue since I close it every iteration in the for loop.
If more code or explanation is required please let me know and I will do my best to assist.
Thank you for taking the time to read this.

So after a bit more Googling and sleeping on it here is what worked for me.
The search function in compareDatabase changed to this:
private Boolean search (String searchValue, Connection connection) {
PreparedStatement ps = null;
try {
ps = connection.prepareStatement("SELECT * FROM lotdatabase where " +
"(Vehicle) = (?)");
ps.setString(1, searchValue);
ResultSet resultSet = ps.executeQuery();
//The following if statement checks if the ResultSet is empty.
if (!resultSet.next()){
resultSet.close();
ps.close();
return false;
}else{
resultSet.close();
ps.close();
return true;
}
} catch (SQLException e) {
e.printStackTrace();
}
return false;
}
And in the other function within compareDatabase I call the search function like this:
if (search(tempDataPoint, connection)) {
System.out.println("MATCH FOUND: " + tempDataPoint);
}else {
System.out.println("NOT FOUND: " + tempDataPoint);
}
This allows me to check the ResultSet and also be sure that it is closed.

Execute a SQL query in a loop

I have this scenario. I will trigger a job in the server and as soon as the job is triggered an entry will be made into the job table with Execution_status_code as 1. I need to wait for some time say 5 mins and recheck the Execution_status_code value. As soon as the value is changed to 2, I need to proceed further.
I am using an existing connection for connecting to the database. I need to execute the SQL and if the SQL output is In progress, I need to wait for some time and then again execute the statement. Do this until the SQL output is success, until then keep waiting.
Below is the code I have tried.
Thread t = new Thread();
java.sql.Connection conn_javaComp = (java.sql.Connection)globalMap.get("conn_tNetezzaConnection_1");
java.sql.Statement st = null;
java.sql.ResultSet rs = null;
String check = null;
String dbquery_javaComp = "select case when EXECUTION_STATUS_CODE = 2 then 'Success' when EXECUTION_STATUS_CODE = 1 then 'In progress' else 'Failure' end as EXECUTION_STATUS_CODE from JOB_BKUP_NCR where JOB_TYPE_CODE="+context.JobTypeCode+" and Load_id = (select max(load_id) from JOB_BKUP_NCR where job_type_code="+context.JobTypeCode+") and START_DATETIME = (select max(START_DATETIME) from JOB_BKUP_NCR where job_type_Code="+context.JobTypeCode+")";
try
{
do
{
st = conn_javaComp.createStatement();
rs = st.executeQuery(dbquery_javaComp);
if(rs.next())
{
check = rs.getString(1);
System.out.println(check);
if (check.equalsIgnoreCase("In Progress"))
{
t.sleep(1000);
System.out.println("thread executed1");
System.out.println(dbquery_javaComp);
System.out.println(check);
}
}
else {
System.out.println(" No data found");
}
}while (!"Success".equals(check));
}
catch (Exception e) {
e.printStackTrace();
} finally {
try {
if( rs != null)
rs.close();
if( st!= null)
st.close();
}
catch (Exception e1) {
e1.printStackTrace();
}
}
The output i am getting is 'In Progress'. The loop is struck at In progress even after i change the value in the database. I am not sure where i am doing wrong. Any suggestions?

You are creating a new statement and a new resultset inside the loop, and so, they should be close inside the loop. I am thinking that your connection got corrupted with multiple statements and resultset without closing them. Please try to close them and see if that work.

The data that you are seeing will be cached.
Try closing and re-opening your DB connection. This may not even be good enough if you are using DB pooling.

There are many things I can foresee going wrong with your code. For once most DBMS will either lock the rows until you commit / close the connection or give you a snapshot of the data instead, hence you don't see the updated value or the transaction that supposed to update it wouldn't go through. Try comitting or close/reopen the transaction per loop iteration.
I would also doubt if this is a good code design as you are doing "polling". Consider if you can find other method of getting notified of the event.

try
{
//declare here your statement and resultset
st = conn_javaComp.createStatement();
rs = st.executeQuery(dbquery_javaComp);
do
{
if(rs.next())
{
check = rs.getString(1);
System.out.println(check);
if (check.equalsIgnoreCase("In Progress"))
{
t.sleep(1000);
System.out.println("thread executed1");
System.out.println(dbquery_javaComp);
System.out.println(check);
}
}
else {
System.out.println(" No data found");
}
}while (!"Success".equals(check));

Combine Select and Update statement

I have tried to research this problem however I cannot find a solution.
Background: I have a small java program using sqlite as its DB. I am trying to update a row counter to keep track of how many time a code is searched, or how many times a row is displayed. (If a row is not displayed it will not be counted). My database table hase three columns {Codes, Description, ItemCount}
Here is code that I used to get a row
private void SrchCodeActionPerformed(java.awt.event.ActionEventevt) {
String sql = "SELECT * FROM emdcodes WHERE Codes like ?"; // SQL command
try {ps = conn.prepareStatement(sql);
ps.setString(1, EMDCODELOOKUP.getText() + "%");
rs = ps.executeQuery();
ResultsTable.setModel(DbUtils.resultSetToTableModel(rs));
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e);
} }
I am using this sql code on a website version and it works. it is written in PHP.
$sqlcount = mysql_query("update emdcodes SET ItemCount = ItemCount +1 Where Codes like '$term%'");
My Question is where and how would I add the counter code to the java progam. The purpose of the counter is to maintain a list of the top 5 items searched for.
I thank anyone for their help.

I am not sure if this is exactly what are you looking for...
private void SrchCodeActionPerformed(java.awt.event.ActionEventevt) {
if (counter <= 5) {
String sql = "SELECT * FROM emdcodes WHERE Codes like ?"; // SQL command
try {ps = conn.prepareStatement(sql);
ps.setString(1, EMDCODELOOKUP.getText() + "%");
rs = ps.executeQuery();
if (rs.first()){
counter++;
}
ResultsTable.setModel(DbUtils.resultSetToTableModel(rs));
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e);
}
}
}
first() ->
Moves the cursor to the first row in this ResultSet object.
Returns:
true if the cursor is on a valid row; false if there are no rows in the result set