How to verify if my JDBC query output has data in it or not - jdbc

Question

I want to verify if my JDBC query output has data in it or not. If it doesn't contain any data then it should print the assertion as false.
I tried using this:
System.out.println("Table contains "+rs.getRow()+" rows");
if (!rs.next())
{
Assert.assertTrue(false);
}
else
{
Assert.assertTrue(true);
}
I tried using as below:
System.out.println("Table contains "+rs.getRow()+" rows");
if (!rs.next())
{
Assert.assertTrue(false);
}
else
{
Assert.assertTrue(true);
}
But it didn't work. So can anyone suggest how to solve this?

Answer 1

If you only need to know, how many rows are in a table, let the DBMS count them with:
select count(*) as noRows from table
And within your java code it will look like this snippet
boolean hasRows= false;
Statement stmt = null;
ResultSet rs = null;
try {
stmt = connection.createStatement();
rs = stmt.executeQuery("select count(*) as noRows from table");
if ( rs.next() ) {
if ( rs.getInt(1) > 0 ) {
hasRows = true;
}
}
} catch (SQLException sqlex ) {
// print or log an error message
} finally {
if ( rs != null ) {
try {
rs.close();
} catch (SQlException sqlex ) {
// print or log an error message
}
}
if ( stmt != null ) {
try {
stmt.close();
} catch (SQlException sqlex ) {
// print or log an error message
}
}
}
Assert.assertTrue(hasRows);
And it could also make sense to close your connection.
This will just return the rows within a table. If you need to know the size of a particular query, I for myself would do it similarly with the query and just replace the fields from the query with the count(*) or count(DISTINCT xyz) command. Try it first out within your sql monitor, because if the query runs to long, you might not be happy.