Update command with special SQL keywords in JDBC - java

I am trying a update an entry in my SQL table which has a column name "from" in JDBC.
Following is the SQL command that I am trying to execute:
sql = "Update email_template set [from]="+"'"+3+"'"+" WHERE id="+idno;
stmt.executeUpdate(sql);
However it shows the following error:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '[from]='Akshit' WHERE id=1' at line


MySQL's way of escaping column names is by using backticks:
sql = "Update email_template set `from`="+"'"+3+"'"+" WHERE id="+idno;


I recommend using java.sql.PreparedStatement when handling SQL in Java. It can be used for batches and ensures malicious SQL is not injected as part of the SQL code.
This is how your code looks with a PreparedStatement:
PreparedStatement stmt = connection.prepareStatement("UPDATE `email_template` SET `from` = ? WHERE id = ?");
stmt.setInt(1, 3);
stmt.setInt(2, idno);
stmt.executeUpdate();
If this is an operation you execute for many rows in one go, replace stmt.executeUpdate() with stmt.addBatch() (likely in some loop) and when you're ready to execute the batched updates you call stmt.executeBatch().
Note that both executeUpdate() and executeBatch() return how many rows were affected; which is something you may want to validate after a commit.

Related

Get row count of successful bulk insert using jdbc from sql server

I have Java code to bulk-insert tab file to SQL Server.
I want to get the count of how many records were inserted. I tried using ##rowcount but I'm getting an error that "Statement did not return a result set".
If I run the bulk insert statement in management studio, I can get the count.
Statement stmt = sqlConnection.createStatement();
ResultSet rs = stmt.executeQuery ("BULK INSERT schema1.table1 FROM 'd:\temp1\file1.tab' SELECT ##rowcount");
Is there any way to get the inserted count?

I'm not familiar with SQL Server but it seems like you'll want to issue an executeUpdate instead of an executeQuery
Statement stmt = sqlConnection.createStatement();
int insertedRowCount = stmt.executeUpdate("BULK INSERT schema1.table1 FROM 'd:\temp1\file1.tab'");

Syntax error in delete statement

I am trying to delete the record from my "student" table, the table has two column rollno and student name.
I am using a PreparedStatement but I am getting some error. I could not understand the error. The error is:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 1
here is my code
String query = "delete from student where rollno = ?";
PreparedStatement pst = con.prepareStatement(query);
pst.setInt(1, 7);
pst.executeUpdate(query);

Likely you are calling the execute like this:
pst.executeUpdate(query);
This will execute the raw query, without the parameter you set before.
You want to execute the prepared query instead, so just use:
pst.executeUpdate();

SQL prepared statement throwing an error about syntax

So I am using SQL with phpMyAdmin. Now I want to make an update to my database with a prepared statement but doind it gives me the following error:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'autor='Lol' WHERE id=44' at line 1
And this is how my statement looks like:
command = connection.prepareStatement("UPDATE books SET name=? author=? WHERE id=?");
command.setString(1, name.getText());
command.setString(2, author.getText());
command.setInt(3, IDx);
command.execute();
Wat is wrong with the statement I have made? It should be working In my opinion.

You need to separate the updated fields in a comma like:
command = connection.prepareStatement("UPDATE books SET name=?, author=? WHERE id=?");

You forgot a comma before author
UPDATE books
SET name = ?, author = ?
WHERE id = ?

Is my JDBC error caused by my SQL query?

Currently i'm writing a JDBC application to manage a MySQL database. I have the delete, insert and select methods functioning with the correct queries. I'm having trouble with the Update method. When using using the following code I receive a MySQL error:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near "",Street",Town",City",PostCode",Age",email",RunningFee'false'Where PID=" at line 1...
private void updateData()
{
Connection con;
try
{
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection(
"jdbc:mysql://localhost/snr","root","");
String sql = "Update participant Set password='"+txtpassword.getText()+"'," +
"lastName='"+txtlastName.getText()+"',firstName='"+
txtfirstName.getText()+"',HouseNumber'"+txtHouseNumber.getText()+"',Street'"+txtStreet.getText()+"',Town'"+txtTown.getText()+"',City'"+txtCity.getText()+"',PostCode'"+txtPostCode.getText()+"',Age'"+txtAge.getText()+"',email'"+txtemail.getText()+"',RunningFee'"+cbRunningFee.isSelected()+"' Where PID='"+txtPID.getText()+"'";
Statement statement = con.createStatement();
statement.execute(sql);
createMessageBox("Updated Successfully");
clearControls();
}
catch(Exception e)
{
createMessageBox(e.getMessage());
}
}
Is there something wrong with my SQL query?

Yes, your query is wrong. You're missing = on a great big bunch of set column/value pairs.
(And please consider using prepared statements and bind variables, SQL injection is just not something you want to be open to.)

Yes there is something wrong with the query. Your way of building query is vulnerable to SQL Injection. Use Parameterized Queries instead of concatenating text like that.
Read this article: Preventing SQL Injection in Java

Not only is your query incorrect, but it may also open you to SQL Interjection Attacks.
You need to parameterize your query by replacing the pasted-in values with question marks, preparing the statement, and executing it. See the tutorial that I linked.
Finally, storing a password as plain text is a very, very bad idea.
String sql = "UPDATE participant SET "+
"password=?, lastName=?, firstName=?, HouseNumber=?, Street=?, Town=?, "+
"City=?,PostCode?,Age=?,email=?,RunningFee=? "+
"WHERE PID=?";
PreparedStatement upd = con.prepareStatement(sql);
upd.setString(1, txtpassword.getText());
upd.setString(2, txtlastName.getText());
// ... and so on
upd.executeUpdate();
con.commit();

You are forgetting some = in your query.
Try
String sql = "Update participant Set password='"+txtpassword.getText()+"'," +
"lastName='"+txtlastName.getText()+"',firstName='"+
txtfirstName.getText()+"',HouseNumber='"+txtHouseNumber.getText()+"',Street='"+
txtStreet.getText()+"',Town='"+txtTown.getText()+"',City='"+txtCity.getText()+
"',PostCode='"+txtPostCode.getText()+"',Age='"+txtAge.getText()+"',email='"+
txtemail.getText()+"',RunningFee='"+cbRunningFee.isSelected()+
"' Where PID='"+txtPID.getText()+"'";

The error 'you have an error in your SQL syntax' is from the sql server and indicates that yes, you do have an error in your query. In these cases I often find it useful to print the constructed query itself, just to check that it is being constructed correctly.
In your case I believe the problem is that you are missing a bunch of "="s, you also probably need to escape your single quotes in the java so they are passed through correctly (replace ' with \').

MySQL batch stmt with Statement.RETURN_GENERATED_KEYS

I am trying to execute 2 sql statements in a batch. the first statement is an insert that uses a auto generated value for its ID. the second statement is an insert to another table but it needs to use the auto generated value from above as part of the insert value
something like (where id is just to show the auto generated field its not defined in sql
stmt.addbatch(insert into table1("id_auto_generated", "foo"));
stmt.addbatch(insert into table2("table1_id", "boo"));
the way I do it now is by using this in my second sql
insert into table2(LAST_INSERT_ID(), "boo");
Problem is its slow even in batch statements its very slow as my batch can be 50,000 inserts.
I wanted to switch to prepared statements but do not know how to use Statement.RETURN_GENERATED_KEYS or LAST_INSERT_ID() with prepared statements.

I'm not sure this is a way you can do this with addBatch except in the manner that you are using. Another thing to try is to abandon the addBatch() method and try turning off auto-commit instead. Then you can use the stmt.getGeneratedKeys();. Something like:
connection.setAutoCommit(false);
stmt.executeUpdate("insert into table1(\"id_auto_generated\", \"foo\") ...");
DatabaseResults results = stmt.getGeneratedKeys();
// extract the id from the results
stmt.executeUpdate("insert into table2(\"table1_id\", \"boo\") ...");
... many more stmts here
connection.commit();
connection.setAutoCommit(true);
Hope this helps.

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