Mysql statement in java not executing

Question

I have a function in Java that is meant to update the description field and the title field of a table in a mysql database that looks like this:

public void updateDescription( String desc, String title, int urlid ) throws SQLException, IOException {
    String cutDesc = desc.substring(0, 99);
    Statement stat = connection.createStatement();
    String query = "UPDATE urls SET description = '"+cutDesc+"', title = '"+title+"' WHERE urlid =" + urlid;
    stat.executeUpdate( query );
    stat.close();
}

When this function is called with:

updateDescription(desc, title, urlID);

Nothing is put into the table. There are no errors, it just seems to ignore it. Any ideas what is wrong here?

Thanks

have you print the query and try to execute it manually on your data base ? — Thomas
– Thomas, Commented Apr 10, 2014 at 8:22
It only fails if the where condition did not fetch any records. — Ravinder Reddy
– Ravinder Reddy, Commented Apr 10, 2014 at 8:35

Dawood ibn Kareem · Accepted Answer · 2014-04-10 08:24:35Z

1

You said nothing is put into the table.

But UPDATE doesn't put things into the table - it only modifies rows that already exist. You need to use INSERT instead of UPDATE.

answered Apr 10, 2014 at 8:24

Dawood ibn Kareem

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5 Comments

Reece Kenney Over a year ago

I'm sorry I was not clear enough. I already have values in the other two columns. In the description and title field at the moment is just a blank value. There are four columns, two of which had values inserted with the following command String query = "INSERT INTO urls VALUES ('"+urlID+"','"+url+"','','')"; Description and title are the final two columns in the query

Dawood ibn Kareem Over a year ago

OK, what is the type of column urlID? The INSERT statement in your comment suggests that it's a character type, but your Java code suggests it's a numeric type. Are you sure that those values have gone into the columns that you think they've gone into?

Reece Kenney Over a year ago

Its is VARCHAR because I have been concatenating it with multiple URLID's separated by commas e.g. 2,3,4,7,8

Dawood ibn Kareem Over a year ago

Is your updateDescription method throwing an SQLException then? Because you're comparing it to a numeric value in your SQL. Also, what is the value in that column, on the row that you actually want to update?

Dawood ibn Kareem Over a year ago

By the way, having multiple values in a single column is usually a bad idea. Is there a reason why you can't have one row per URL ID?

cadrian · Accepted Answer · 2014-04-10 08:23:56Z

0

connection.commit();

or

connection.setAutoCommit(true);

should help.

answered Apr 10, 2014 at 8:23

cadrian

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Comments

user2881767 · Accepted Answer · 2014-04-10 11:24:53Z

0

public void updateDescription( String desc, String title, int urlid ) throws SQLException, IOException {
    String cutDesc = desc.substring(0, 99);
    Statement stat = connection.createStatement();
    String query = "UPDATE urls SET description = '"+cutDesc+"', title = '"+title+"' WHERE urlid ='" + urlid+"'";
    stat.executeUpdate( query );
    stat.close();
}

Try the above code, as you have stated that urlid is VARCHAR in database

answered Apr 10, 2014 at 11:24

user2881767

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3 Comments

Reece Kenney Over a year ago

Still nothing is being inserted into the title or description columns

user2881767 Over a year ago

Print out string 'query' and try running the SQL query with the value for urlid directly on the database. Check if there is any change as your query seems fine

Reece Kenney Over a year ago

I printed the query and then copy and pasted it exactly how it appeared and it worked! So I can't think why it wouldn't work in the function?

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