Postgres::Handler - Builds upon DBD::Pg for advanced CGI web apps
Postgres::Handler builds upon the foundation set by DBI and DBD::Pg to create a superset of methods for tying together some of the basic interface concepts of DB management when used in a web server environment. Postgres::Handler is meant to build upon the strengths of DBD::Pg and DBI and add common usability features for a variety of Internet applications.
Postgres::Handler encapsulates error message handling, information message handling, simple caching of requests through a complete iteration of a server CGI request. You will also find some key elements that hook the CGI class to the DBI class to simplify data IO to & from web forms and dynamic pages.
# Instantiate Object # use Postgres::Handler; my $DB = Postgres::Handler->new(dbname=>'products',dbuser=>'postgres',dbpass=>'pgpassword'); # Retrieve Data & List Records # $DB->PrepLEX('SELECT * FROM products'); while ($item=$DB->GetRecord()) { print "$item->{PROD_ID}\t$item->{PROD_TITLE}\t$item->{PROD_QTY}\n"; } # Add / Update Record based on CGI Form # assuming objCGI is an instatiated CGI object # if the CGI param 'prod_id' is set we update # if it is not set we add # my %cgimap; foreach ('prod_id','prod_title','prod_qty') { $cgimap{$_} = $_; } $DB->AddUpdate( CGI=>$objCGI , CGIKEY=>'prod_id', TABLE=>'products', DBKEY=>'prod_id', hrCGIMAP=>\%cgimap );
CGI::Carp CGI::Util Class::Struct DBD::Pg 1.43 or greater (fixes a bug when fetching Postgres varchar[] array data) DBI
None by default.
Create a new Postgres::Handler object.
dbname => name of the database to connect to dbuser => postgres user dbpass => password for that user
Get/set the data hash - this is where data fields are stored for the active record.
Returns the database handle for the DB connection.
Get/set postgres user's password.
Get/set database name. Simple string name of the database.
Get/set postgres username.
Returns the statement handle for the active record selection.
Adds a new record or updates an existing record in the database depending on whether or not a specific CGI parameter has been set. Useful for processing a posted form that contains form fields that match data fields. Pre-populate the form field that contains the database key field and an update occurs. Set it to blank and a new record is added. Your database key field should have a default value that is unique and should be set as type 'PRIMARY KEY'. We always use serial primary key to auto-increment our keys when adding new records.
-- -- Table: xyz -- CREATE TABLE xyz ( xyz_pkid serial primary key, xyz_update timestamp default now(), xyz_ipadd char(32) );
If a key is provided but is doesn't match anything in the existing data then the update fails, UNLESS... CHECKKEY=> 1 in which case it will attempt to add the record. Your CGI->DB key hash reference should look something like this: %mymap = ( tablefld_name => 'form_name', tablefld_ssn => 'htmlform_ssn' ); And is passed with a simple \%mymap as the hrCGIMAP parameter to this function. -or- Even better, name your CGI form fields the same thing as your Postgres DB field names. Then you can skip the map altogether and just provide the CGISTART variable. All fields that start with the the CGISTART string will be mapped. Want to map every field? Set CGISTART = '.'.
CGI => a CGI object from the CGI:: module DBKEY => the name of the key field within the table defaults to Postgres::Handler Object Property <table>!PGHkeyfld must be provided - or - the <table>!PGHkeyfld option must have been setup when creating a new Postgres::Handler object TABLE => the name of the table to play with CGISTART or hrCGIMAP must be set (see below)
CGISTART => map all CGI object fields starting with this string into equivalently named database fields only used when hrCGIMAP is not set CGIKEY => the CGI parameter name that stores the data key defaults to DBKEY CHECKKEY => set to 1 to perform ADD if the DBKEY is not found in the database. DBSTAMP => the name of the timestamp field within the table defaults to Postgres::Handler Object Property <table>!PGHtimestamp DONTSTAMP => set to 1 to stop timestamping timestamp field must be set hrCGIMAP => a reference to a hash that contains CGI params as keys and DB field names as values MD5 => the name of the md5 encrypted field within the table defaults to Postgres::Handler Object Property <table>!PGHmd5 REQUIRED => array reference pointing to array that holds list of CGI params that must contain data VERBOSE => set to 1 to set lastinfo() = full command string otherwise returns 'INSERT' or 'UPDATE' on succesful execution BOOLEANS => array reference pointing to the array that holds the list of database field booleans that we want to force to false if not set by the equivalently named CGI field RTNSEQ => set to a sequence name and AddUpdate will return the value of this sequence for the newly added record. Useful for getting keys back from new records.
Either adds or updates a record in the specified table. Record is added if CGI data key [1] is blank or if CHECKKEY is set and the value of the key is not already in the database. Record is updated if CGI data key [2] contains a value.
1 for success, get message with lastinfo() 0 for failure, get message with lasterror()
Do DBH Command and log any errors to the log file. [0] = SQL command [1] = Die on error [2] = return error on 0 records affected [3] = quiet mode (don't log via carp) Set the object 'errortype' data element to 'simple' for short error messages. i.e. $self->data('errortype') = 'simple';
1 for success 0 for failure, get message with lasterror
Retreive a field from the specified table.
DATA => Which data item to return, must be of form "table!field" KEY => The table key to lookup in the database Used to determine if our current record is still valid. Also used as default for WHERE, key value is searched for in the PGHkeyfld that has been set for the Postgres::Handler object.
WHERE => Use this where clause to select the record instead of the key FORCE => Force Reload
The value of the field. Returns 0 and lasterror() is set to a value if an error occurs lasterror() is blank if there was no error
my $objPGDATA = new Postgres::Handler::HTML ('mytable!PGHkeyfld' => 'id'); my $lookupID = '01123'; my $data = $objPGDATA->Field(DATA=>'mytable!prod_title', KEY=>$lookupID); my $lookupSKU = 'SKU-MYITEM-LG'; my $data = $objPGDATA->Field(DATA=>'mytable!prod_title', WHERE=>"sku=$lookupSKU");
Retrieves the record in a hash reference with uppercase field names. rtype not set or set to 'HASHREF', Calls fetchrow_hashref('NAME_uc') from the specified SQL statement. rtype not set or set to 'ARRAY', Calls fetchrow_array() from the specified SQL statement. rtype not set or set to 'ITEM', Calls fetchrow() from the specified SQL statement.
[0] or -name select from the named statement handle, if not set defaults to the last active statement handle [1] or -rtype 'HASHREF' (default) or 'ARRAY' or 'ITEM' - type of structure to return data in [2] or -finish set to '1' to close the named statement handle after returning the data
the hashref or array or scaler on success 0 for failure, get message with lasterror
Retrieve the latest error produced by a Postgres::Handler object.
The error message
Retrieve the latest info message produced by a Postgres::Handler object.
The info message
Retrieve a named statement handle
The handle, as requested.
Prepare an SQL statement and returns the statement handle, log errors if any.
[0] or -cmd - required -statement [1] or -exec - execute flag (PREPLE) or die flag (PREPLEX) [2] or -die - die flag (PREPLE) or null (PREPLEX) [3] or -param - single parameter passed to execute [4] or -name - store the statement handle under this name
1 for success
Same as PrepLE but also executes the SQL statement
[0] or -cmd - required -statement [1] or -die - die flag (PREPLE) or null (PREPLEX) [2] or -param - single parameter passed to execute [3] or -name - store the statement handle under this name
Quote a parameter for SQL processing via the DBI::quote() function Sets the data handle if necessary.
Using these methods without understanding the implications of playing with their values can wreak havoc on the code. Use with caution...
Internal function to set data handles Returns Data Handle If you don't want the postgres username and password littering your perl code, create a subclass that overrides SetDH with DB specific connection info.
Allows for either ordered or positional parameters in a method call AND allows the method to be called as EITHER an instantiated object OR as an direct class call.
[0] - self, the instantiated object [1] - the class we are looking to instantiate if necessary [2] - reference to hash that will get our named parameters [3] - an array of the names of named parameters IN THE ORDER that the positional parameters are expected to appear [4] - extra parameters, positional or otherwise
Populates the hash refered to in the first param with keys & values
An object of type class, newly instantiated if necessary.
sub MyMethod() { my $self = shift; my %options; $self = SetMethodParms($self,'MYCLASS::SUBCLASS', \%options, [PARM1,PARM2,PARM3], @_ ); print $options{PARM1} if ($options{PARM2} ne ''); print $options{PARM3}; }
Prepare a hash reference for mapping CGI parms to DB fields typically used with AddUpdate() from Postgres::Handler.
hrCGIMAP - reference to hash that contains the map CGI - the CGI object CGISTART - map all fields starting with this text CGIKEY - the cgi key field BOOLEANS - address to list of boolean fields
@boolist = qw(form_field1 form_field2); $item->CGIMap(CGI => $objCGI, hrCGIMAP=>\%cgimap, CGISTART=>'cont_', CGIKEY=>'cont_id', BOOLEANS=>\@boolist);
Some methods allow for parameters to be passed in via both positional and named formats. If you decide to use named parameters with these "bi-modal" methods you must prefix the parameter with a hyphen. # Positional Example # use Postgres::Handler; my $DB = Postgres::Handler->new(dbname=>'products',dbuser=>'postgres',dbpass=>'pgpassword'); $DB->PrepLEX('SELECT * FROM products'); # Named Example # use Postgres::Handler; my $DB = Postgres::Handler->new(dbname=>'products',dbuser=>'postgres',dbpass=>'pgpassword'); $DB->PrepLEX( -cmd => 'SELECT * FROM products' );
# Instantiate Object # use Postgres::Handler; my $DB = Postgres::Handler->new(dbname=>'products',dbuser=>'postgres',dbpass=>'pgpassword'); # Retrieve Data & List Records # $DB->PrepLEX('SELECT * FROM products'); while ($item=$DB->GetRecord()) { print $item->{PROD_ID}\t$item->{PROD_TITLE}\t$item->{PROD_QTY}\n"; } # Add / Update Record based on CGI Form # assuming objCGI is an instatiated CGI object # if the CGI param 'prod_id' is set we update # if it is not set we add # my %cgimap; foreach ('prod_id','prod_title','prod_qty') { $cgimap{$_} = $_; } $DB->AddUpdate( CGI=>$objCGI , CGIKEY=>'prod_id', TABLE=>'products', DBKEY=>'prod_id', hrCGIMAP=>\%cgimap );
Lance Cleveland, Advanced Internet Technology Consultant Contact info@charlestonsw.com for more info.
Charleston Software Associates (CSA) is and advanced internet technology consulting firm based in Charleston South Carolina. We provide custom software, database, and consulting services for small to mid-sized businesses. For more information, or to schedule a consult, visit our website at www.CharlestonSW.com
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(c) 2005, Charleston Software Associates This script is covered by the GNU GENERAL PUBLIC LICENSE. View the license at http://www.charlestonsw.com/community/gpl.txt or at http://www.gnu.org/copyleft/gpl.html
v2.2 - Apr 2006 Fixed problem with SetDH database handle management v2.1 - Mar 2006 Added RTNSEQ feature to AddUpdate so we can get back the key of a newly added record v2.0 - Feb 2006 Moved CGI::Carp outside of the package to prevent perl -w warnings v1.9 - Feb 2006 Update Field() to prevent SIGV error when WHERE clause causes error on statement Field() now returns 0 + lasterror() set to value if failed execute returns fldval + lasterror() is blank if execution OK v1.8 - Jan 2006 Bug fix on PrepLE and PrepLEX for perl -w compatability Added DoLE param to return error status (0) if the command affects 0 records '0E0' Added DoLE param to keep quiet on errors (do not log to syslog via carp) Documentation updates v1.5 - Nov 2005 Fixed @BOOLEANS on AddUpdate to force 'f' setting instead of NULL if blank or 0 v1.5 - Oct 2005 Fixed return value error on AddUpdate() v1.4 - Aug 2005 Minor patches v1.3 - Jul 17 2005 Minor patches Now requires DBD::Pg version 1.43 or greater v1.2 - Jun 10 2005 GetRecord() mods, added 'ITEM' test file fix in distribution created yml file for added requisites on CPAN v1.1 - Jun 9 2005 pod updates Field() cache bug fix GetRecord() expanded, added finish option Moved from root "PGHandler" namespace to better-suited "Postgres::Handler" v0.9 - May 2 2005 pod updates AddUpdate() updated, CGIKEY optional - defaults to DBKEY AddUpdate() updated, BOOLEANS feature added GetRecord() updated, added check for sth active before executing Field() fixed hr cache bug and data bug and trap non-set hr issue v0.8 - Apr 26 2005 Fixed GetRecord() (again) - needed to check $DBI::errstr not $err v0.7 - Apr 25 2005 Added error check on ->Field to ensure hashref returned from getrecord Added CGIMAP method Invoke CGIMAP from within AddUpdate if missing map Fixed GetRecord Return system v0.5 - Apr/2005 Added DBI error trap on DoLE function Added named statement handles for multiple/nested PrepLE(X) capability Added VERBOSE mode to AddUpdate Added NAME to retrieved named statements via GetRecord Updated FIELD to use named statement handles v0.4 - Apr/2005 Fixed some stuff v0.3 - Apr/2005 Added REQUIRED optional parameter to AddUpdate Improved documentation Quoted DBKEY on add/update to handle non-numeric keys v0.2 - Mar/2005 - Added error messages to object Fixed issues with Class:Struct and the object properties Updated AddUpdate to use named parameters (hash) for clarity v0.1 - Dec/2004 Initial private release
To install Postgres::Handler, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Postgres::Handler
CPAN shell
perl -MCPAN -e shell install Postgres::Handler
For more information on module installation, please visit the detailed CPAN module installation guide.