From 2073b4db4ac71fc6cf2c9c171cbfc22bfe0f1576 Mon Sep 17 00:00:00 2001 From: LtWorf Date: Wed, 22 Sep 2010 12:53:36 +0000 Subject: [PATCH] - Internally uses set instead of lists to describe relation's content - Discards the old and not so functional tlb format git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@250 014f5005-505e-4b48-8d0a-63407b615a7c --- CHANGELOG | 2 + relational/relation.py | 125 ++++++++++++++------------------------ relational_gui/maingui.py | 2 +- 3 files changed, 47 insertions(+), 82 deletions(-) diff --git a/CHANGELOG b/CHANGELOG index 7177910..9653f61 100644 --- a/CHANGELOG +++ b/CHANGELOG @@ -1,6 +1,8 @@ 0.12 - Removed encoding from .desktop file (was deprecated) - Added manpage for relational-cli +- Internally uses set instead of lists to describe relation's content +- Discards the old and not so functional tlb format 0.11 - Font is set only on windows (Rev 206) diff --git a/relational/relation.py b/relational/relation.py index 6d7e931..2458f90 100644 --- a/relational/relation.py +++ b/relational/relation.py @@ -25,67 +25,50 @@ class relation (object): A relation can be represented using a table Calling an operation and providing a non relation parameter when it is expected will result in a None value''' - def __init__(self,filename="",comma_separated=True): + def __init__(self,filename=""): '''Creates a relation, accepts a filename and then it will load the relation from that file. If no parameter is supplied an empty relation is created. Empty relations are used in internal operations. By default the file will be handled like a comma separated as described in RFC4180, but it can also be handled like a space separated file (previous default format) setting to false the 2nd parameter. - The old format is deprecated since it doesn't permit fields - with spaces, you should avoid using it.''' + The old format is no longer supported.''' if len(filename)==0:#Empty relation - self.content=[] + self.content=set() self.header=header([]) return #Opening file fp=file(filename) - if comma_separated: - reader=csv.reader(fp) #Creating a csv reader - self.header=header(reader.next()) # read 1st line - self.content=[] - for i in reader.__iter__(): #Iterating rows - self.content.append(i) - else: #Old format - self.header=header(fp.readline().replace("\n","").strip().split(" ")) + + reader=csv.reader(fp) #Creating a csv reader + self.header=header(reader.next()) # read 1st line + self.content=set() - self.content=[] - row=fp.readline() - while len(row)!=0:#Reads the content of the relation - self.content.append(row.replace("\n","").strip().split(" ")) - row=fp.readline() + for i in reader.__iter__(): #Iterating rows + self.content.add(tuple(i)) #Closing file fp.close() - def save(self,filename,comma_separated=True): + def save(self,filename): '''Saves the relation in a file. By default will save using the csv format as defined in RFC4180, but setting comma_separated to False, it will use the old format with space separated values. - The old format is deprecated since it doesn't permit fields - with spaces, you should avoid using it.''' + The old format is no longer supported.''' fp=file(filename,'w') #Opening file in write mode - if comma_separated: #writing csv - writer=csv.writer(fp) #Creating csv writer + + writer=csv.writer(fp) #Creating csv writer - #It wants an iterable containing iterables - head=[] - head.append(self.header.attributes) - writer.writerows(head) + #It wants an iterable containing iterables + head=(self.header.attributes,) + writer.writerows(head) - #Writing content, already in the correct format - writer.writerows(self.content) - else: #Writing in the old, deprecated, format - res="" - res+=" ".join(self.header.attributes) - - for r in self.content: - res+="\n" - res+=" ".join(r) - fp.write(res) + #Writing content, already in the correct format + writer.writerows(self.content) fp.close() #Closing file + def _rearrange_(self,other): '''If two relations share the same attributes in a different order, this method will use projection to make them have the same attributes' order. @@ -105,6 +88,7 @@ class relation (object): newt=relation() newt.header=header(list(self.header.attributes)) for i in self.content: + #Fills the attributes dictionary with the values of the tuple for j in range(len(self.header.attributes)): if len(i[j])>0 and i[j].isdigit(): attributes[self.header.attributes[j]]=int(i[j]) @@ -117,7 +101,7 @@ class relation (object): try: if eval(expr,attributes): - newt.content.append(i) + newt.content.add(i) except Exception,e: raise Exception("Failed to evaluate %s\n%s" % (expr,e.__str__())) return newt @@ -134,7 +118,7 @@ class relation (object): for i in self.content: for j in other.content: - newt.content.append(i+j) + newt.content.add(i+j) return newt @@ -174,8 +158,7 @@ class relation (object): row=[] for j in ids: row.append(i[j]) - if attributes_same_count or row not in newt.content: - newt.content.append(row) + newt.content.add(tuple(row)) return newt def rename(self,params): @@ -192,7 +175,8 @@ class relation (object): if (newt.header.rename(old,new)) == False: return None - newt.content=list(self.content) + #TODO only copy the link and mark the new relation as read only + newt.content=set(self.content) return newt def intersection(self,other): @@ -207,10 +191,7 @@ class relation (object): newt=relation() newt.header=header(list(self.header.attributes)) - #Adds only element not in other, duplicating them - for e in self.content: - if e in other.content: - newt.content.append(list(e)) + newt.content=self.content.intersection(other.content) return newt def difference(self,other): @@ -225,10 +206,7 @@ class relation (object): newt=relation() newt.header=header(list(self.header.attributes)) - #Adds only element not in other, duplicating them - for e in self.content: - if e not in other.content: - newt.content.append(list(e)) + newt.content=self.content.difference(other.content) return newt def division(self,other): '''Division operator @@ -272,13 +250,7 @@ class relation (object): newt=relation() newt.header=header(list(self.header.attributes)) - #Adds element from self, duplicating them all - for e in self.content: - newt.content.append(list(e)) - - for e in other.content: - if e not in newt.content: - newt.content.append(list(e)) + newt.content=self.content.union(other.content) return newt def thetajoin(self,other,expr): '''Defined as product and then selection with the given expression.''' @@ -344,34 +316,32 @@ class relation (object): for l in noid: item.append(j[l]) - newt.content.append(item) + newt.content.add(tuple(item)) added=True #If it didn't partecipate, adds it if not added: item=list(i) for l in range(len(noid)): item.append("---") - newt.content.append(item) + newt.content.add(tuple(item)) return newt def join(self,other): '''Natural join, joins on shared attributes (one or more). If there are no shared attributes, it will behave as cartesian product.''' - shared=[] - for i in self.header.attributes: - if i in other.header.attributes: - shared.append(i) + + #List of attributes in common between the relations + shared=list(set(self.header.attributes).intersection(set(other.header.attributes))) newt=relation() #Creates the new relation - #Adds all the attributes of the 1st relation + #Adding to the headers all the fields, done like that because order is needed newt.header=header(list(self.header.attributes)) - - #Adds all the attributes of the 2nd, when non shared for i in other.header.attributes: if i not in shared: newt.header.attributes.append(i) + #Shared ids of self sid=self.header.getAttributesId(shared) #Shared ids of the other relation @@ -394,7 +364,7 @@ class relation (object): for l in noid: item.append(j[l]) - newt.content.append(item) + newt.content.add(tuple(item)) return newt def __eq__(self,other): @@ -412,12 +382,7 @@ class relation (object): return False #Non shared attribute #comparing content - if len(self.content) != len(other.content): - return False #Not the same - for i in self.content: - if i not in other.content: - return False - return True + return self.content==other.content def __str__(self): '''Returns a string representation of the relation, can be printed with @@ -433,7 +398,6 @@ class relation (object): m_len[col]=len(i) col+=1 - res="" for f in range(len(self.header.attributes)): res+="%s"%(self.header.attributes[f].ljust(2+m_len[f])) @@ -482,8 +446,9 @@ class relation (object): self.content.remove(i) for k in range(len(keys)): new_tuple[f_ids[k]]=str(dic[keys[k]]) - self.content.append(new_tuple) + self.content.add(tuple(new_tuple)) return affected + def insert(self,values): '''Inserts a tuple in the relation. This function will not insert duplicate tuples. @@ -499,11 +464,9 @@ class relation (object): for i in values: t.append(str(i)) - if t not in self.content: - self.content.append(t) - return 1 - else: - return 0 + prevlen=len(self.content) + self.content.add(tuple(t)) + return len(self.content)-prevlen def delete(self,expr): '''Delete, expr must be a valid boolean expression, can contain field names, @@ -513,7 +476,7 @@ class relation (object): Returns the number of affected rows.''' attributes={} affected=len(self.content) - new_content=[] #New content of the relation + new_content=set() #New content of the relation for i in self.content: for j in range(len(self.header.attributes)): if i[j].isdigit(): @@ -526,7 +489,7 @@ class relation (object): attributes[self.header.attributes[j]]=i[j] if not eval(expr,attributes): affected-=1 - new_content.append(i) + new_content.add(i) self.content=new_content return affected diff --git a/relational_gui/maingui.py b/relational_gui/maingui.py index 37d11db..8e84ca0 100644 --- a/relational_gui/maingui.py +++ b/relational_gui/maingui.py @@ -195,7 +195,7 @@ class Ui_Form(object): #Patch provided by Angelo 'Havoc' Puglisi self.relations[str(res[0].toUtf8())]=relation.relation(str(filename.toUtf8()),use_csv) else: #name was decided by caller - self.relations[name]=relation.relation(filename,use_csv) + self.relations[name]=relation.relation(filename) self.updateRelations() def insertTuple(self):