Owning a butcher knife is not illegal. Walking downtown and and stroking the knife sure would be.
Knives are classified as either tools, or prohibited by design, which would include knives such as butterfly knives/balisongs, switch blades/autos, push/punch daggers, knives with brass knuckles and so on. If a knife is not prohibited by design, then the same rules apply to it as do to hammers, axes, screw drivers and so on.
It is perfectly legal to own knives and swords that aren't prohibited by design in Canada so long as your purpose for purchasing and or carrying it is to use it as a tool. Remember, Canadian law does not allow you to carry a knife for the purpose of "self defence". Carrying a knife for the purpose of "self defence" would identify your knife as a weapon, which is not permitted. Some places that you cannot carry a knife on you to are airports, court rooms and some other government buildings, as well as businesses that serve alcohol and such.
Basically, if you have an intention to use it as self defense or a weapon, its no good. I try to stay away from knives that look like weapons in public. (Cold Steel AK-47 with a black blade comes to mind)
You also asked about fixed blades.... For myself personally, I don't have a logical reason to carry one around myself, so I think its a no go for me. I wouldn't feel comfortable having a fixed blade in public, I could see people thinking it as a weapon. Some folders have a utility look to them, so they are easier to pass off as a tool.
If you use it for opening boxes or its needed for your occupation, or anything BUT to do physycal harm to a human being its good to go! If I ever get any questions, I just say I use it for my job, I am an electrician. (Think of a cop walking into a hospital and taking way a doctors scalpel, or a campers hatchet - that just doesn't make sense!) - If you have a logical reason to carry a knife, don't worry.