Notes
   Note: 
    
     Not all functions are supported by all builds. It depends on your
     libpq (The PostgreSQL C client library) version and how libpq is
     compiled. If PHP PostgreSQL extensions are missing, then it is because
     your libpq version does not support them. 
    
   
  
   Note: 
    
     Most PostgreSQL functions accept connection as
     the optional first parameter. If it is not provided, the last opened
     connection is used. If it doesn't exist, functions return false.
    
   
   Note: 
    
     PostgreSQL automatically folds all identifiers (e.g. table/column names)
     to lower-case values at object creation time and at query time. 
     To force the use of mixed or upper case identifiers, you must escape
     the identifier using double quotes ("").
    
   
   Note: 
    
     PostgreSQL does not have special commands for fetching database schema
     information (eg. all the tables in the current database).  Instead, there
     is a standard schema named information_schema in
     PostgreSQL 7.4 and above containing
     system views with all the necessary information, in an easily
     queryable form.  See the » PostgreSQL Documentation
     for full details.