Help with PHP questions

["Cyndi Bradberry" <CyndiB@xxxxxxxx>]

Ok, I am finally getting a chance to work on my PHP book again. I am
using The IBM I Programmer's Guide to PHP, page 246 figure 8.12 as my
source code;
 
<?php
//Set the database name
$tableName = 'SYSTABLES' ;
$libName = 'QSYS2' ;
 
//Create the connection to the System i Relational Database
if (($dbh = db2_connect('BOISE','OPERIT','ITOPER')) === false) {
      echo 'connection failed.<br>' ;
      echo db2_conn_errormsg().'<br>' ;
      die() ;
}
 
//Retrieve a result set with the column info for the
//file specified at the top of the script.
if (($cols = db2_columns( $dbh, null, $libName, $tableName, '%' )) ===
FALSE) {
      echo 'colums retrieval failed. <BR>' ;
      echo db2_stmt_errormsg(). '<BR>' ;
      die() ;
}
 
//Fetch the first row and output the file name
// and library name from the result set.
$column = db2_fetch_assoc($cols) ;
echo 'FileTable: ' ;
echo $column["TABLE_SCHEM"]."/".$column["TABLE_NAME"]."<BR>" ;
 
//Loop thru all the result set rows and list all the column names.
 
do {
      echo $column["COLUMN_NAME"]."<BR>" ;
} while ($column = db2_fetch_assoc($cols)) ;
      
?>
 
I get a triangle with an exclamation point next to the } while line at
the bottom of the code, which when I hover over, it shows this:
 
Multiple annotations found at this line:
            - Line Breakpoint: db2Script1.php 
             [line: 31 ]
            - bool-assign : Assignment in condition
 
The script runs (now, not sure why) and I get this output:
 
FileTable: QSYS2/SYSTABLES
TABLE_NAME
TABLE_OWNER
TABLE_TYPE
COLUMN_COUNT
ROW_LENGTH
TABLE_TEXT
LONG_COMMENT
TABLE_SCHEMA
LAST_ALTERED_TIMESTAMP
SYSTEM_TABLE_NAME
SYSTEM_TABLE_SCHEMA
FILE_TYPE
BASE_TABLE_SCHEMA
BASE_TABLE_NAME
BASE_TABLE_MEMBER
SYSTEM_TABLE
SELECT_OMIT
IS_INSERTABLE_INTO
IASP_NUMBER
ENABLED
MAINTENANCE
REFRESH
REFRESH_TIME
MQT_DEFINITION
ISOLATION
PARTITION_TABLE
TABLE_DEFINER
 
Should I be able to change to any file/library (Table/Schema) on the
system and get a list of the columns in the table ?  
When I change the names in $tableName and $libName, I only get
FileTable: / as a response.
 
I know I have to be missing something simple here. Manual references
that will explain things are enjoyed.
 
Cyndi B.
Boise, ID