I can delete specific rows using manual SQL query command. But can not delete from QLineEdit. How to bind with QLineEdit?
Here is my code:
person_name = ui->txt_UserName->text ();
mobile_number = ui->txt_Pass->text ();
//delete values
QString deleteStatement = "DELETE FROM phonebook_info WHERE user_name = ':person_name'";
query->bindValue (":person_name", person_name);
query->exec (deleteStatement);
if(query->exec ()){
QMessageBox::information (this, "Information!", "Row Deleted.", QMessageBox::Ok);
ui->statusBar->showMessage ("Row Deleted.");
} else {
QMessageBox::critical (this, "Information!", "Row not Deleted.", QMessageBox::Ok);
ui->statusBar->showMessage ("Row not Deleted.");
}
query executed but not delete. What am I doing wrong?
The syntax doesn't look right and you call query->exec() twice. This is how you should run the prepared statement:
QSqlQuery query = new QSqlQuery(databaseInstance);
bool ok = query->prepare(deleteStatement);
if (!ok) {
qWarning() << "SQL error:" << deleteStatement;
}
query->bindValue(":person_name", person_name);
query->exec();
Related
I'm trying to simply count the amount of records that has a 'true' status.
this is the SQLite table structure:
CREATE TABLE Suppliers(ID INTEGER PRIMARY KEY AUTOINCREMENT,Name varchar(50),Number varchar(15),URL varchar(70),Status bool,ShippingCost integer)
I am then calling a query from QT as follows:
int SQLiteController::ActiveSupplierCount()
{
int count = 0;
QSqlQuery Query;
Query.prepare("SELECT *"
"FROM Suppliers"
"WHERE Status = (:Status)");
Query.bindValue(":Status", true);
Query.exec();
qDebug() << Query.lastError();
while(Query.next() == true)
{
count++;
}
qDebug() << count;
return count;
};
The last error returned here is "Parameter count mismatch"
and I cannot figure out why... There is only 1 parameter, and I assign to that 1 parameter.
Try to add some extra spaces after each line of your query like this
Query.prepare("SELECT * "
"FROM Suppliers "
"WHERE Status = (:Status)");
I'm doing two queries to a SQL Server database, the first query returns the Result Set with data, but the second query always returns the Result Set empty. If I do the query in the SQL SERVER, it does it well. I have tried to make another query: SELECT TOP 10 * FROM TABLE and always returns empty.
<%
String url,ssql;
int i,j,k;
int reg[]=new int[256];
try{
Class.forName("com.microsofto.sqlserver.jdbc.SQLServerDriver");
url="jdbc:sqlserver://localhost/;databaseName=acsc;user=user;password=1234";
Connection conn = DriverManager.getConnection(url);
Statement stc = conn.createStatement();
ssql="SELECT Nombre,max(Registro) FROM Tabla Group by Nombre order by Nombre";
ResultSet rsc= stc.executeQuery(ssql);
i=1;
while(rsc.next()){
reg[i]=rsc.getInt(2);
i++;
}
j=0;
do{
//ssql="SELECT * FROM Tabla Where Registro="+String.valueOf(reg[j]);
ssql="SELECT TOP 10 * FROM Tabla";
rsc= stc.executeQuery(ssql);
if(!(rsc.getRow()==0)){
out.println(rsc.getString(1)+" "+rsc.getString(2)+" "+rsc.getString(3));
}else{
out.println("vacio");
}
j++;
}while(j<i);
}catch(SQLException se){
out.println(se.toString());
}
%>
There are two problems with your code. The only one you need to fix is that you're not using Parameters in your SQL query. See
public static void executeStatement(Connection con) {
try(PreparedStatement pstmt = con.prepareStatement("SELECT LastName, FirstName FROM Person.Contact WHERE LastName = ?");) {
pstmt.setString(1, "Smith");
ResultSet rs = pstmt.executeQuery();
while (rs.next()) {
System.out.println(rs.getString("LastName") + ", " + rs.getString("FirstName"));
}
}
// Handle any errors that may have occurred.
catch (SQLException e) {
e.printStackTrace();
}
}
Using an SQL Statement with Parameters
Thank you for your response and sorry for not having responded before.
I have tried using prepareStatement, but the ResultSet kept returning empty.
I finally found where I had the problem, if!(Rsc.getRow()==0)) always returned 0, even if the ResulSet had records.
I have removed that part of the program and I have placed while rsc.next() and it works correctly.
What is the second problem that my code has?
Thanks greetings
Im creating a student profile for our project in school and it's my first time to make this.
This is my query for my jTable (mouseclicked) I've created in netbeans
int row = jTable1.getSelectedRow();
String tc = jTable1.getModel().getValueAt(row, 0).toString();
try {
String query ="select * from CAREPOINT_STUDENT where NAME="+tc+" ";
pst= (OraclePreparedStatement) ungabelio1.prepareStatement(query);
rs = (OracleResultSet) pst.executeQuery();
if(rs.next()){
String NAME_ID = rs.getString("NAME");
String AGE_ID = rs.getString("AGE");
String ADDRESS_ID = rs.getString("ADDRESS");
String NUM_ID = rs.getString("NUM");
String COURSE_ID = rs.getString("COURSE");
String SPECIAL_ID = rs.getString("SPECIAL");
String SCHOOL_ID = rs.getString("SCHOOL");
String DOWNPAY_ID = rs.getString("DOWNPAY");
String DISCOUNT_ID = rs.getString("DISCOUNT");
String BALANCE_ID = rs.getString("BALANCE");
String REVSCHED_ID = rs.getString("REVSCHED");
String EMAIL_ID = rs.getString("EMAIL");
NAME.setText(NAME_ID);
AGE.setText(AGE_ID);
ADDRESS.setText(ADDRESS_ID);
NUM.setText(NUM_ID);
COURSE.setText(COURSE_ID);
SPECIAL.setText(SPECIAL_ID);
SCHOOL.setText(SCHOOL_ID);
DOWNPAY.setText(DOWNPAY_ID);
DISCOUNT.setText(DISCOUNT_ID);
BALANCE.setText(BALANCE_ID);
REVSCHED.setText(REVSCHED_ID);
EMAIL.setText(EMAIL_ID);
}
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e);
}
}
When I run the program and tried to click the data (A Student Profile like name,age,school, etc..) that I created and printed inside the jtable (mouseclicked), I get this problem "ORA-00933: SQL command not properly ended"
Aside from that, I also have another problem which I created 2 jbutton called "DELETE" which means it will delete the data(Student profile) that I filled up and "UPDATE" which means to reedit the data(Student profile) that I filled up.
this is the query of my "DELETE" jbutton in netbeans
try {
String query;
query = "DELETE FROM CAREPOINT_STUDENT where NAME="+NAME.getText()+" ";
pst= (OraclePreparedStatement) ungabelio1.prepareStatement(query);
pst.execute();
JOptionPane.showMessageDialog(null, "Successfully deleted!");
fetch();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e);
}
}
and this is the query of my "UPDATE" jbutton in netbeans
try {
String query;
query = "update CAREPOINT_STUDENT set AGE=?,ADDRESS=?,NUM=?,COURSE=?,SPECIAL=?,SCHOOL=?,DOWNPAY=?,DISCOUNT=?,BALANCE=?,REVSCHED=?,EMAIL=? where NAME="+NAME.getText()+"";
pst= (OraclePreparedStatement) ungabelio1.prepareStatement(query);
pst.setString(1,AGE.getText());
pst.setString(2,ADDRESS.getText());
pst.setString(3, NUM.getText());
pst.setString(4, COURSE.getText());
pst.setString(5, SPECIAL.getText());
pst.setString(6, SCHOOL.getText());
pst.setString(7, DOWNPAY.getText());
pst.setString(8, DISCOUNT.getText());
pst.setString(9, BALANCE.getText());
pst.setString(10, REVSCHED.getText());
pst.setString(11, EMAIL.getText());
pst.executeUpdate();
JOptionPane.showMessageDialog(null, "Successfully updated!");
fetch();
} catch (Exception e){
JOptionPane.showMessageDialog(null, e);
}
}
when I run the program and click those 2 buttons, I get the same problem "ORA-00936: missing expression"
I really appreciate and I hope that somebody would help me to fix this problem. So that I can gain some little knowledge about sql/oracle.
Sorry for my bad english.
Avoid concatenating parameters as strings; use prepared statements.
Otherwise you'll run in all kind of troubles, like escaping issues for special characters, SQL Injection, etc.
For example, a safer way of running your SQL statement could be:
String query = "select * from CAREPOINT_STUDENT where NAME = ?";
pst = (OraclePreparedStatement) ungabelio1.prepareStatement(query);
pst.setString(1, tc);
rs = (OracleResultSet) pst.executeQuery();
Note: Assembling a SQL statement as a string is still useful for cases when you want to do some dynamic SQL. Even then, use ? for parameters and apply them as shown above.
You may need some extra single quotes so you query will read:
select * from CAREPOINT_STUDENT where NAME='Entered name';
Adjust your code:
String query ="select * from CAREPOINT_STUDENT where NAME='"+tc+"' ";
I'm able to execute sql statements by writing the sql codes (Insert etc) on Eclipse and it is being displayed into sql server correctly. Connection has been done. But what should I do when a user wants to add data through a GUI interface (text field) and the data need to get stored into the database automatically ??
my code in the ADD button, but i'm getting the Error: java.lang.NullPointerException ! Help please..
try {
String pid = ProductID.getText();
String sql = "insert into Products_tbl values (' " +pid + " ')";
// Running the sql query
rs = st.executeQuery(sql);
int count = 0;
while (rs.next()) {
count = count + 1;
}
if (count == 1) {
JOptionPane.showMessageDialog(null, "Welcome");
}
else if (count > 1) {
JOptionPane.showMessageDialog(null,"Duplicate User Access Denied");
}
else {
JOptionPane.showMessageDialog(null, " User Not Found ");
}
}
catch (Exception ex) {
System.out.println("Error: " + ex);
}
1- Using (' " +pid + " ')" is not safe because SQL injection may occur. Use SqlParameters instead. Please check:
https://www.w3schools.com/sql/sql_injection.asp
2- I am pretty sure something is wrong with the line: rs = st.executeQuery(sql);
Here, I bet the value of st is null. Make sure that your connection variable is defined and set correctly and you created the statement like below:
st = connection.createStatement();
You can also try executeupdate(query) instead of executequery(query) like:
int flag = st.executeUpdate(query);
Ref: https://docs.oracle.com/javase/7/docs/api/java/sql/Statement.html#executeUpdate%28java.lang.String%29
3- Please use printStackTrace() method while printing the error in the catch blog, the error message would be more understandable.
System.out.println("Error: " + ex.printStackTrace());
I'm really struggling with a bug that did not appear on my dev environment, only once deployed in test.
I'm using a prepared Statement to run around 30 000 query in a row. The query check for the similarity of a string with what's in our database, using the oracle fuzzy method.
The column checked is indexed, but, don't know why, it fails randomly after some iterations, saying that index does not exists.
I don't understand what's going on, as the index really exists. My method never rebuild or delete the index so there is no reason for this error to appear ...
public List<EntryToCheck> checkEntriesOnSuspiciousElement(List<EntryToCheck> entries, int type,int score, int numresults, int percentage) throws Exception {
Connection connection = null;
PreparedStatement statementFirstName = null;
PreparedStatement statementLastname = null;
int finalScore = checkScore(score);
int finalNumResults = checkNumResults(numresults);
int finalPercentage = checkPercentage(percentage);
try {
connection = dataSource.getConnection();
StringBuilder requestLastNameOnly = new StringBuilder("SELECT SE.ELEMENT_ID, SE.LASTNAME||' '||SE.FIRSTNAME AS ELEMENT, SCORE(1) AS SCORE ");
requestLastNameOnly.append("FROM BL_SUSPICIOUS_ELEMENT SE ");
requestLastNameOnly.append("WHERE CONTAINS(SE.LASTNAME, 'fuzzy({' || ? || '},' || ? || ',' || ? || ', weight)', 1)>? ");
requestLastNameOnly.append((type > 0 ? "AND SE.ELEMENT_TYPE_ID = ? " : " "));
requestLastNameOnly.append("ORDER BY SCORE DESC");
statementLastname = connection.prepareStatement(requestLastNameOnly.toString());
for (EntryToCheck entryToCheck : entries) {
ResultSet rs;
boolean withFirstName = (entryToCheck.getEntryFirstname() != null && !entryToCheck.getEntryFirstname().equals(""));
statementLastname.setString(1, entryToCheck.getEntryLastname().replaceAll("'","''"));
statementLastname.setInt(2, finalScore);
statementLastname.setInt(3, finalNumResults);
statementLastname.setInt(4, finalPercentage);
if(type > 0){
statementLastname.setInt(5, type);
}
System.out.println("Query LastName : " + entryToCheck.getEntryLastname().replaceAll("'","''") );
rs = statementLastname.executeQuery();
while (rs.next()) {
Alert alert = new Alert();
alert.setEntryToCheck(entryToCheck);
alert.setAlertStatus(new AlertStatus(new Integer(AlertStatusId.NEW)));
alert.setAlertDate(new Date());
alert.setBlSuspiciousElement(new BlSuspiciousElement(new Integer(rs.getInt("ELEMENT_ID"))));
alert.setMatching(rs.getString("ELEMENT") + " (" + rs.getInt("SCORE") + "%)");
entryToCheck.addAlert(alert);
}
}
}
catch (Exception e) {
e.printStackTrace();
throw e;
}
finally {
DAOUtils.closeConnection(connection, statementLastname);
}
return entries;
}
Really don't know what to look at ...
Thanks !
F
I never used Oracle text tables but my advice is:
Make sure that no one else is executing DDL statements on the table simultaneously.
Also, make sure that, index you have is context index.
Create an index for your column where you want to apply search
........................................
CREATE INDEX "MTU219"."SEARCHFILTER" ON "BL_SUSPICIOUS_ELEMENT " ("LASTNAME")
INDEXTYPE IS "CTXSYS"."CONTEXT" PARAMETERS ('storage CTXSYS.ST_MTED_NORMAL SYNC(ON COMMIT)');
..........................................