PHP and SQL Server - Thoughts

I converted a project from PHP/MySql to PHP/MSSQL once upon a time. I'll provide my notes here of what I found as I was converting. I think for some reason I ended up using the odbc commands instead of mssql because they seemed to be more reliable, especially if you are doing multiple queries in the same page - don't ask me why, that's just what I found.

My command syntax comparison chart:

*mysql cmd*         *mssql cmd*         *odbc cmd*          *Notes*
mysql_errno         mssql_errno         odbc_error  
mysql_error         mssql_error         odbc_errormsg   
mysql_select_db     mssql_select_db     unneeded    
mysql_query         mssql_query         odbc_exec           odbc_exec requires the resource link parameter ($db)
mysql_affected_rows mssql_rows_affected odbc_num_rows   
mysql_num_rows      mssql_num_rows      odbc_num_rows   
mysql_fetch_object  mssql_fetch_object  odbc_fetch_object   
mysql_close         mssql_close         odbc_close          odbc_close requires the resource link parameter ($db)
mysql_fetch_array   mssql_fetch_array   odbc_fetch_array    
mysql_result        mssql_result        odbc_result         odbc_result cannot take a row index as parameter; must cycle with odbc_fetch_row
mysql_fetch_row     mssql_fetch_row     odbc_fetch_row      odbc_fetch_row does not return the result; use odbc_fetch_row with odbc_result

My code snippets replacement chart for conversion (I had literally done this project by generating a list of FIND/REPLACE strings and applied them across the entire code base until there were no more errors left :-):

*old mysql code*                                        *new odbc code*                             *Notes*
for ($i = 0; $i < mysql_num_rows($result); $i++)        while (odbc_fetch_row($result))             odbc_num_rows doesn't usually work for finding how many rows returned
mysql_result($result, $i                                odbc_result($result                         odbc_result can't go request the result for a specific row, have to use odbc_fetch_row
NOW()                                               GETDATE()                                   NOW() function in mysql is GETDATE() in sql server
if (connect_db())                                   if ($db = connect_db())                     In mysql, you don't have to keep track of the $db resource - with odbc, you do
if (!connect_db())                                  if (!($db = connect_db()))                  See notes on previous entry
                                                    odbc_fetch_row($result);                    When retrieving a single row, you have to call fetch_row with odbc, but not with mysql
if (mysql_num_rows($result) == 1)                   if (odbc_fetch_row($result))                odbc_num_rows usually doesn't work, so for a single row, just do if odbc_fetch_row
if (mysql_errormsg() || mysql_num_rows($ASISHSresult) == 0)     if (!odbc_errormsg() && !odbc_fetch_row($ASISHSresult)) 
limit ##, ##                                        row_number() over (order by ???)            limit function in mysql has to be translated to row_number() function in odbc (also must be inc. by 1 to offset off-by-1 error between mysql and sql server)
match(body) against ('expr' in boolean mode)        contains(body, 'expr') or containstable(Body, 'expr')   fulltext matching in sql server has different syntax than mysql
text_column = value                                 cast(text_column as varchar(good_size)) = value     mysql can compare text column to value, sql server cannot without varchar casting
                                                    odbc_free_result($result);                  When you make a lot of connections, you must free results or your future connections may be ignored

One last point. If you make use of the built-in encryption commands to encrypt passwords as we did in this project, you'll need to do the encryption in php instead of mysql.