mysqldb interface vs Prolog

packages/python/examples/mysql.pl

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+
+:- use_module(library(python)).
+
+:- use_module(library(lists)).
+
+:- python_import('MySQLdb').
+
+:- initialization(main).
+
+main :- 
+	python_import(pyx),
+	ex(X),
+	flush_output,
+	fail.
+main.
+
+ex(open) :-
+	connect,
+% execute SQL query using execute() method.
+        := $cursor:execute('SELECT VERSION()'),
+% Fetch a single row using fetchone() method.
+        Data := cursor:fetchone(_),
+	Data = t(Version),
+	format( "Database version : ~a~n ", [ Version ]),
+	close.
+
+ex(create) :-
+	connect,
+% Drop table if it already exist using execute() method.
+	:= $cursor:execute('DROP TABLE IF EXISTS EMPLOYEE'),
+        % Create table as per requirement
+	sql := 'CREATE TABLE EMPLOYEE (
+         FIRST_NAME  CHAR(20) NOT NULL,
+         LAST_NAME  CHAR(20),
+         AGE INT,  
+         SEX CHAR(1),
+         INCOME FLOAT )',
+	:= $cursor:execute($sql),
+	close.
+
+ex(insert) :-
+	connect,
+% Prepare SQL query to INSERT a record into the database.
+	catch(add, _, rollback), 
+   	close.
+
+add :-
+	customer(First, Last, Age, Sex, Income),
+	format(atom(Sql), 'INSERT INTO EMPLOYEE(FIRST_NAME,
+         LAST_NAME, AGE, SEX, INCOME)
+         VALUES (\'~a\', \'~a\', ~d, \'~a\', ~g)',
+	 [ First, Last, Age, Sex, Income ]),
+	% Execute the SQL command
+	:= $cursor:execute(Sql),
+	fail.
+add :- 
+	% Commit your changes in the database
+        := $db:commit(_).
+
+rollback :-
+	:= db:rollback(_).
+
+connect :-
+	db := connect('localhost','testuser','test123','TESTDB' ),
+	:= $db:set_character_set('utf8'),
+% prepare a cursor object using cursor() method
+        cursor := db:cursor(_),
+	:= $cursor:execute('SET NAMES utf8;'),
+	:= $cursor:execute('SET CHARACTER SET utf8;'),
+	:= $cursor:execute('SET character_set_connection=utf8;').
+
+close :-
+% disconnect from server
+	:= db:close(_).
+
+% Open database connection
+ex(read) :-
+	connect,
+% Prepare SQL query to SELECT a record from the database.
+	sql := 'SELECT * FROM EMPLOYEE \
+               WHERE INCOME > 1000',
+	catch(try, _, except),
+	close.
+
+try:-
+   % Execute the SQL command
+	:= $cursor:execute($sql),
+   % Fetch all the rows in a list of lists.
+	Results := $cursor:fetchall(_),
+	Results =.. [_|LResults],
+	member(t(Fname, Lname, Age, Sex, Income), LResults),
+      % Now print fetched result
+	format("fname=~a, lname=~a, age=~d, sex=~a, income=~g~n",
+    [Fname, Lname, Age, Sex, Income ]),
+	fail.
+try.
+
+except:-
+   format('Error: unable to fecth data', []).
+
+% disconnect from server
+
+customer('João', 'Matos', 40, 'M', 2000).
+customer('Maria', 'Söderling', 20, 'F', 3000).
+%customer('毛', '泽东', 44, 'M', 500).
+%customer('রবীন্দ্রনাথ', 'ঠাকুর', 30, 'M', 8000).