Here is my MySql table:
I want to show the output of the query in commandline as below:
I have written the code below to loop but I am getting only the first row, What i have to modify ??
ResultSet rs2 = stmt.executeQuery(table_retrive);
String[] cols = new String[itemList.size()];
int[] rec =new int[itemList.size()];
for (int i = 0; i < itemList.size(); i++) {
while (rs2.next()) {
cols[i] =(String) itemList.get(i);
rec[i] = rs2.getInt(cols[i]);
System.out.println(rec[i]+" ");
}
}
Your two loops are wrong. Start at i=0 and then iterate once over the whole ResultSet, filling yor first array position. When this is done, i is incremented and you try to iterate the ResultSet a second time but the cursor is at the end of the ResultSet, so rs2.next() returns false and the code will not be executed.
So you have two Solutions:
Handle the loops correctly. Unfortunately I do not know, what you are trying to do anyways because this is some C-like code without OOP, which doesn't show semantics and then you have this itemList which seems to hold preset values and you read out of this list, which column to take for the i-th position. This seems odd. Maybe switching the loops does the desired: Start with the while and nest the for.
Reset the cursor of the ResultSet after the while with rs2.beforeFirst(). WARNING: This could throw a SQLFeatureNotSupportedException. Not all Databases can move the cursor backwards. This is of course a very ugly solution, since you should first parse the whole row a once.
Try to use printf() Or format() method. It is same as printf method in c lang. you can pass parameters and difference. Look at link1
And link 2
Example : System.out.printf("%d%5s%10d", 5,"|",10);
output : 5 | 10
Using this the I got all the values but in one row :
while (rs2.next()) {
for (int i = 0; i < itemList.size(); i++) {
cols[i] =(String) itemList.get(i);
rec[i] = rs2.getInt(cols[i]);
System.out.print(rec[i]+" ");
}
}
But I need to divide like the rows.
Usage of the inner loop is your problem.
You can enhance your code to remove the usage of the second loop in your code, it basically does nothing. You can loop over your result set and in the same loop using the incremented variable to persist the values accordingly.
The code shown half implemented in your question, hence it will be difficult to give you exactly what need to be done. Nevertheless, here's an attempt to resolve the problem for you:
while (rs2.next()) {
System.out.println(rs2.getInt(1) + "\t |" + rs2.getString(2) + "\t |" + rs2.getString(3));
}
Based on the column names from the table in the question, assuming that column2 and column3 are String's.
You can add the necessary details to this code to complete it according to your usecase, but I've just taken the example of showing a record in one line.
EDIT:
OP has his own way of programming, but to satisfy his question in the comment - this is how you can do it.
while (rs2.next()) {
for (int i = 0; i < itemList.size(); i++)
{
cols[i] =(String) itemList.get(i);
rec[i] = rs2.getInt(cols[i]);
System.out.print(rec[i]+"\t |");
}
System.out.println();
}
Related
Ok that may not make much sense so I'll try and clarify with code, I've got a basic Result set like so: -
ResultSet results = stmt.executeQuery(constants.execQueueSQL());
I then want to iterate through this with a while loop like so: -
while (results.next()){
String val1 = results.getString("col 1");
String val2 = results.getString("col 2");
String val3 = results.getString("col 3");
}
Now, when I debug this within eclipse I can see that before executing the while line the currentRow is already showing as 1 in results, and as I step to each line within the while the currentRow count increases by 1!!
I know that I have 4 rows returned but by the time I get to retrieving col 3 I'm already out, and all subsequent values are wrong as they are being obtained from separate lines, why is this...?
I am using the below line in JAVA Embedding to assign value to a BPEL Invoke DB adapter input variable.
setVariableData("S2C_insert_InputVariable","TmpInvStoc3Collection","/ns8:TmpInvStoc3Collection/ns8:TmpInvStoc3/ns8:batchid","12345");
Now i want to put this statement in a while loop within java and want to repeat this for n iterations. I want to place a loop variable in the collection but I dont know how to do this.
I am looking for something like below.
setVariableData("S2C_insert_InputVariable","TmpInvStoc3Collection","/ns8:TmpInvStoc3Collection/ns8:TmpInvStoc3[$loop_variable]/ns8:batchid","12345");
Please let me know how to achieve this
Regards
Murali
This is based on the assumption that value is a function of i and cannot be calculated in the BPEL.
String qry = "";
for (int i = 0; i < n; i++)
{
value = SomeFunctionThatRequiresJavaRatherThanBPEL(i);
qry = "/ns8:TmpInvStoc3Collection/ns8:TmpInvStoc3[" + i + "]/ns8:batchid";
setVariableData("S2C_insert_InputVariable","TmpInvStoc3Collection",qry,value);
}
The code could be more efficient but it should do what you want.
This is the code I am working on:
if(connection.doDatabaseRead(findSQL))
{
ResultSet retRES = connection.getResultSet();
int i = 0;
// did we find anything
while( retRES.next() )
{
//read result from query
suiteNum.add(retRES.getString(i)); // this is the problem
i++;
//let other threads breathe
Thread.yield();
}
}
suiteNum is a string vector
When I try to add the database results to the vector the code crashes with this error.
java.sql.SQLException: Column Index out of range, 0 > 1.
I have the same piece of code working elsewhere in the program but I use real numbers like 0, 1 and 2 instead of i and it works fine.
As I do not know how many results the database request will have I need it to be dynamic but it will only work hard coded.
How can I make it work with i ?
The argument to getString is the column index, not the row index as you seem to think. The function returns the value of the given column in the current row, while next advances the cursor to the next row.
You probably mean:
suiteNum.add(retRES.getString(1));
in which case you can lose i altogether.
Java ResultSet objects are 1-indexed in this regard. The first element is at 1, not 0. See the javadoc.
EDIT: That's true too, but indeed the problem is this appears to be used as a row index! it's certainly the column.
This is your problem:
i = 0;
...
retRES.getString(i);
ResultSet.getString(i) gets a String from column number i
You want something like
while(retRes.next()) {
add(retRes.getString(1);
}
column index starts from 1
As I do not know how many results the database request will have I need it to be dynamic but it will only work hard coded. How can I make it work with i
ResultSetMetaData rsMetaData = rs.getMetaData();
int numberOfColumns = rsMetaData.getColumnCount();
See Also
ResultSetMetaData
Let your i start with 1 as specified in the API docs
if(connection.doDatabaseRead(findSQL))
{
ResultSet retRES = connection.getResultSet();
int i = 1;
// did we find anything
while( retRES.next() )
{
//read result from query
suiteNum.add(retRES.getString(i)); // this is the problem
i++;
//let other threads breathe
Thread.yield();
}
}
I have a table similar to the following:
Part #
Price
Status
1st Part #
$1.00
OK
2nd Part #
$2.00
Discontinued
Nth Part #
$N.00
Reordered
My java code will be looking for the status of "Nth Part #" where I have no idea how big the table is, how many columns it has, and no idea what N is (until run time). In Ruby/WATIR, I would have used the table's id to grab it's HTML, and then used Ruby to iterate over the rows until the part # matched, and then check that row's corresponding status in the Status column (whichever column that might be, but it's set in the hd header's row).
Selenium's standard table lookup function selenium.getTable("table.1.2") only works for static tables that contain the same contents for each test. The overkill selenium.get_html_source is a waste since selenium knows how to find the table already, plus then I have to parse the entire web page.
Any ideas on how I can grab the html of the table, and what would be the best way to iterate over the rows and/or columns?
Thanks in advance.
The easiest thing to do would be to use getTable like this
selenium.getTable("table." + (1 + n) + ".3")
to get the "Status" cell for the nth row if you know what n will be at runtime.
If you are trying to iterate over all of the rows in the table, you could do something like this
try {
for(int n = 1; true; n++) {
String cellContents = selenium.getTable("table." + n + ".3");
//do something with n
}
}
catch {
//handle end of table
}
or, alternatively
final int rowCount = (int)selenium.getXPathCount("id('table')/tbody/tr");
for(int n = 1; n < rowCount; n++) {
String cellContents = selenium.getTable("table." + n + ".3");
}
Remember that in getTable(locator.row.column), row and column start at 1.
Not exactly what you're asking for, but I solved a similar problem by assigning the unique id (part number it sounds like in your case) to be the html id of the tr. Then I used the Selenium xpath locators to get the row and columns I needed for my test.
I want to get the size of the ResultSet inside the while loop.
Tried the code below, and I got the results that I want. But it seems to be messing up with result.next() and the while loop only loops once if I do this.
What's the proper way of doing this?
result.first();
while (result.next()){
System.out.println(result.getString(2));
System.out.println("A. " + result.getString(5) + "\n" + "B. " + result.getString(6) + "\n" + "C. " + result.getString(7) + "\n" + "D. " + result.getString(8));
System.out.println("Answer: ");
answer = inputquiz.next();
result.last();
if (answer.equals(result.getString(10))) {
score++;
System.out.println(score + "/" + result.getRow());
} else {
System.out.println(score + "/" + result.getRow());
}
}
What's the proper way of doing this?
Map it to a List<Entity>. Since your code is far from self-documenting (you're using indexes instead of column names), I can't give a well suited example. So I'll take a Person as example.
First create a javabean class representing whatever a single row contains.
public class Person {
private Long id;
private String firstName;
private String lastName;
private Date dateOfBirth;
// Add/generate c'tors/getters/setters/equals/hashcode and other boilerplate.
}
(a bit decent IDE like Eclipse can autogenerate them)
Then let JDBC do the following job.
List<Person> persons = new ArrayList<Person>();
while (resultSet.next()) {
Person person = new Person();
person.setId(resultSet.getLong("id"));
person.setFirstName(resultSet.getString("fistName"));
person.setLastName(resultSet.getString("lastName"));
person.setDataOfBirth(resultSet.getDate("dateOfBirth"));
persons.add(person);
}
// Close resultSet/statement/connection in finally block.
return persons;
Then you can just do
int size = persons.size();
And then to substitute your code example
for (int i = 0; i < persons.size(); i++) {
Person person = persons.get(i);
System.out.println(person.getFirstName());
int size = persons.size(); // Do with it whatever you want.
}
See also:
How to check if there is zero-or-one result or one-or-more results and their size
you could do result.last(); and call result.getRow(); (which retrieves the current row number) to get count. but it'll have load the all the rows and if it's a big result set, it might not be very efficient. The best way to go about is to do a SELECT COUNT(*) on you query and get the count like it's demonstrated in this post, beforehand.
This is a tricky question.
Normally, result.last() scrolls to the end of the ResultSet, and you can't go back.
If you created the statement using one of the createStatement or prepareStatement methods with a "resultSetType" parameter, and you've set the parameter to ResultSet.TYPE_SCROLL_INSENSITIVE or ResultSet.TYPE_SCROLL_SENSITIVE, then you can scroll the ResultSet using first() or relative() or some other methods.
However, I'm not sure if all databases / JDBC drivers support scrollable result sets, and there are likely to be performance implications in doing this. (A scrollable result set implies that either the database or the JVM needs to buffer the entire resultset somewhere ... or recalculate it ... and that's expensive for a large resultset.)
The way of getting size of ResultSet, No need of using ArrayList etc
int size =0;
if (rs != null)
{
rs.beforeFirst();
rs.last();
size = rs.getRow();
}
Now You will get size, And if you want print the ResultSet, before printing use following line of code too,
rs.beforeFirst();
There are also another way to get the count from DB.
Note :
This column gets updated when DBA'S do realtime statistics
select num_rows from all_Tables where table_name ='<TABLE_NAME>';