Perl Database – Just Enough Pepper

Overview Use the DBI package Define all connection info Connect to DB use DBI; Define all connection info Connect to DB Prepare an sql statement text Execute the statement Your preparation variable will hold the result Fetch the result one row at a time

Connect Info needed to connect What connection type (dbi driver): mysql Dbi – database interface What database name: (dbi_dsn): your db What user : (dbi_user): your user What password: (dbi_password): your password Set into environment variables or on connect command

Setting Env Variables for DBI $ENV{"DBI_DRIVER"} = "mysql"; $ENV{"DBI_DSN"} = "pepperdb"; $ENV{"DBI_USER"} = "your user"; $ENV{"DBI_PASS"} = "your password";

Make the connection $dbh=DBI->connect() or die "Error opening database: $DBI::errstr\n"; $dbh is your connection variable now. Ask $dbh for anything you want from the database $DBI::errstr holds last error message $dbh can be whatever name you want

Prepare SQL Statement $sth=$dbh->prepare("SELECT * from tutorials_tbl;") or die "Prepare failed: $DBI::errstr\n"; Create a statement object It needs an sql statement string Build it in a string or right in the prepare command argument $sth holds what you plan to execute now It knows it is working with $dbh

Execute your SQL statement $sth->execute() or die "Couldn't execute query: $DBI::errstr\n"; $sth now holds all the rows your query returned Same thing you would see when you ran the query on mysql

Fetch your results $sth holds the resulting rows, but you want them. Ask $sth to send back an array of the columns of one row at a time: $sth ->fetchrow_array Put the fetched array into variables, as many as you expect (one per column) ( $id, $name) = $sth ->fetchrow_array

Repeat for all rows Surround with while: while (( $id, $name) = $sth ->fetchrow_array) { print "$name has ID $id\n"; }

Clean-up Close the statement object Disconnect from the database $sth->finish(); Disconnect from the database $dbh->disconnect || die "Failed to disconnect\n";

Database summary Use the DBI package Define all connection info Connect to DB Prepare an sql statement text Execute the prepared statement Your preparation variable will hold the result Fetch the result one row at a time

Web + Database Create a perl script that uses a preset search word input form Insert your code inside the yourpage method Fill in your env variables for db connection Connect, Prepare a statement, Execute Query Fetch and Display your results Place script in public_html Set permissions (chmod o+rx your script.pl) Run as www.adelphi.edu/~<your dir>/<yourscript>