1 files changed, 223 insertions, 0 deletions
diff --git a/src/interfaces/python/pg.py b/src/interfaces/python/pg.py
new file mode 100644
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+++ b/src/interfaces/python/pg.py
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+# pgutil.py
+# Written by D'Arcy J.M. Cain
+
+# This library implements some basic database management stuff
+# It includes the pg module and builds on it
+
+from _pg import *
+import string, re, sys
+
+# utility function
+# We expect int, seq, decimal, text or date (more later)
+def _quote(d, t):
+	if t in ['int', 'decimal', 'seq']:
+		if d == "": return 0
+		return "%s" % d
+
+	if t == 'bool':
+		if string.upper(d) in ['T', 'TRUE', 'Y', 'YES', 1, '1', 'ON']:
+			return "'t'"
+		else:
+			return "'f'"
+
+	if d == "": return "null"
+	return "'%s'" % string.strip(re.sub('\'', '\'\'', "%s" % d))
+
+class DB:
+	"""This class wraps the pg connection type"""
+
+	def __init__(self, *args):
+		self.db = apply(connect, args)
+		self.attnames = {}
+		self.pkeys = {}
+		self.debug = None	# For debugging scripts, set to output format
+							# that takes a single string arg.  For example
+							# in a CGI set to "%s<BR>"
+
+		# Get all the primary keys at once
+		for rel, att in self.db.query("""SELECT
+							pg_class.relname, pg_attribute.attname
+						FROM pg_class, pg_attribute, pg_index
+						WHERE pg_class.oid = pg_attribute.attrelid AND
+							pg_class.oid = pg_index.indrelid AND
+							pg_index.indkey[0] = pg_attribute.attnum AND 
+							pg_index.indisprimary = 't'""").getresult():
+			self.pkeys[rel] = att
+
+	def pkey(self, cl):
+		# will raise an exception if primary key doesn't exist
+		return self.pkeys[cl]
+
+	def get_attnames(self, cl):
+		# May as well cache them
+		if self.attnames.has_key(cl):
+			return self.attnames[cl]
+
+		query = """SELECT pg_attribute.attname, pg_type.typname
+					FROM pg_class, pg_attribute, pg_type
+					WHERE pg_class.relname = '%s' AND
+						pg_attribute.attnum > 0 AND
+						pg_attribute.attrelid = pg_class.oid AND
+						pg_attribute.atttypid = pg_type.oid"""
+
+		l = {}
+		for attname, typname in self.db.query(query % cl).getresult():
+			if re.match("^int", typname):
+				l[attname] = 'int'
+			elif re.match("^oid", typname):
+				l[attname] = 'int'
+			elif re.match("^text", typname):
+				l[attname] = 'text'
+			elif re.match("^char", typname):
+				l[attname] = 'text'
+			elif re.match("^name", typname):
+				l[attname] = 'text'
+			elif re.match("^abstime", typname):
+				l[attname] = 'date'
+			elif re.match("^date", typname):
+				l[attname] = 'date'
+			elif re.match("^bool", typname):
+				l[attname] = 'bool'
+			elif re.match("^float", typname):
+				l[attname] = 'decimal'
+			elif re.match("^money", typname):
+				l[attname] = 'money'
+			else:
+				l[attname] = 'text'
+
+		self.attnames[cl] = l
+		return self.attnames[cl]
+
+	# return a tuple from a database
+	def get(self, cl, arg, keyname = None):
+		if keyname == None:			# use the primary key by default
+			keyname = self.pkeys[cl]
+
+		fnames = self.get_attnames(cl)
+
+		if type(arg) == type({}):
+			# To allow users to work with multiple tables we munge the
+			# name when the key is "oid"
+			if keyname == 'oid': k = arg['oid_%s' % cl]
+			else: k = arg[keyname]
+		else:
+			k = arg
+			arg = {}
+
+		# We want the oid for later updates if that isn't the key
+		if keyname == 'oid':
+			q = "SELECT * FROM %s WHERE oid = %s" % (cl, k)
+		else:
+			q = "SELECT oid AS oid_%s, %s FROM %s WHERE %s = %s" % \
+				(cl, string.join(fnames.keys(), ','),\
+					cl, keyname, _quote(k, fnames[keyname]))
+
+		if self.debug != None: print self.debug % q
+		res = self.db.query(q).dictresult()
+		if res == []:
+			raise error, \
+				"No such record in %s where %s is %s" % \
+								(cl, keyname, _quote(k, fnames[keyname]))
+			return None
+
+		for k in res[0].keys():
+			arg[k] = res[0][k]
+
+		return arg
+
+	# Inserts a new tuple into a table
+	def insert(self, cl, a):
+		fnames = self.get_attnames(cl)
+		l = []
+		n = []
+		for f in fnames.keys():
+			if a.has_key(f):
+				if a[f] == "": l.append("null")
+				else: l.append(_quote(a[f], fnames[f]))
+				n.append(f)
+
+		try:
+			q = "INSERT INTO %s (%s) VALUES (%s)" % \
+				(cl, string.join(n, ','), string.join(l, ','))
+			if self.debug != None: print self.debug % q
+			a['oid_%s' % cl] = self.db.query(q)
+		except:
+			raise error, "Error inserting into %s: %s" % (cl, sys.exc_value)
+
+		# reload the dictionary to catch things modified by engine
+		return self.get(cl, a, 'oid')
+
+	# update always works on the oid which get returns
+	def update(self, cl, a):
+		q = "SELECT oid FROM %s WHERE oid = %s" % (cl, a['oid_%s' % cl])
+		if self.debug != None: print self.debug % q
+		res = self.db.query(q).getresult()
+		if len(res) < 1:
+			raise error,  "No record in %s where oid = %s (%s)" % \
+						(cl, a['oid_%s' % cl], sys.exc_value)
+
+		v = []
+		k = 0
+		fnames = self.get_attnames(cl)
+
+		for ff in fnames.keys():
+			if a.has_key(ff) and a[ff] != res[0][k]:
+				v.append("%s = %s" % (ff, _quote(a[ff], fnames[ff])))
+
+		if v == []:
+			return None
+
+		try:
+			q = "UPDATE %s SET %s WHERE oid = %s" % \
+							(cl, string.join(v, ','), a['oid_%s' % cl])
+			if self.debug != None: print self.debug % q
+			self.db.query(q)
+		except:
+			raise error, "Can't update %s: %s" % (cl, sys.exc_value)
+
+		# reload the dictionary to catch things modified by engine
+		return self.get(cl, a, 'oid')
+
+	# At some point we will need a way to get defaults from a table
+	def clear(self, cl, a = {}):
+		fnames = self.get_attnames(cl)
+		for ff in fnames.keys():
+			if fnames[ff] in ['int', 'decimal', 'seq', 'money']:
+				a[ff] = 0
+			elif fnames[ff] == 'date':
+				a[ff] = 'TODAY'
+			else:
+				a[ff] = ""
+
+		a['oid'] = 0
+		return a
+
+	# Like update, delete works on the oid
+	# one day we will be testing that the record to be deleted
+	# isn't referenced somewhere (or else PostgreSQL will)
+	def delete(self, cl, a):
+		try:
+			q = "DELETE FROM %s WHERE oid = %s" % (cl, a['oid_%s' % cl])
+			if self.debug != None: print self.debug % q
+			self.db.query(q)
+		except:
+			return "Can't delete %s: %s" % (cl, sys.exc_value)
+
+		return None
+
+
+	# The rest of these methods are for convenience.  Note that X.method()
+	# and X.db.method() are equivalent
+	def query(self, query): return self.db.query(query)
+	def reset(self): self.db.reset()
+	def getnotify(self): self.db.getnotify()
+	def inserttable(self): self.db.inserttable()
+
+	# The following depend on being activated in the underlying C code
+	def putline(self): self.db.putline()
+	def getline(self): self.db.getline()
+	def endcopy(self): self.db.endcopy()
+	def locreate(self): self.db.locreate()
+	def getlo(self): self.db.getlo()
+	def loimport(self): self.db.loimport()
+