Non-First Normal Form natural join operation
I have 2 tables in non-first normal form:
What would be the result of the NATURAL JOIN operation of these two table?
database relational-database natural-join
edited Nov 23 '18 at 21:23
nvogel
20.9k12962
asked Nov 23 '18 at 13:49
noobcodernoobcoder
498
add a comment |
I have 2 tables in non-first normal form:
What would be the result of the NATURAL JOIN operation of these two table?
database relational-database natural-join
edited Nov 23 '18 at 21:23
nvogel
20.9k12962
asked Nov 23 '18 at 13:49
noobcodernoobcoder
498
1
Please read & act on How to Ask, hits googling 'stackexchange homework' & the downvote arrow mouseover text. Quote the definition(s) you are using. Show/justify your work/reasonin following them. The first place you are stuck explain about why. PS Please use text, not images/links, for text (including code, tables & ERDs). Use a link/image only for convenience to supplement text and/or for what cannot be given in text. And never give a diagram without a legend/key. Make your post self-contained.
– philipxy
Nov 23 '18 at 19:44
1
What relations are those grids pictures of? You don't have an attribute name topping your columns & you don't have a single value for an attribute in a row. Suggest you rewrite them so you do. We can guess that the third column in each has attribute name X--is that right? We can guess that the value for an X attribute is the obvious relation made from the array of values & attributes C & D--is that right? (You are confusing something about attribute names & types.) Quote your textbook's definitions of "relation" & "natural join" (etc), give the relation values clearly & show work using them.
– philipxy
Nov 23 '18 at 19:53
1
PS If you made proper headings that were sets/lists of attribute names and just replaced the attribute values by xN, what would your answer be? PS If you were given those grids, how were you told to interpret them as relations? PS What does this have to do with your tag object-relational-model? PS "1NF" has no single meaning.
– philipxy
Nov 23 '18 at 20:00
add a comment |
I have 2 tables in non-first normal form:
What would be the result of the NATURAL JOIN operation of these two table?
database relational-database natural-join
edited Nov 23 '18 at 21:23
nvogel
20.9k12962
asked Nov 23 '18 at 13:49
noobcodernoobcoder
498
I have 2 tables in non-first normal form:
What would be the result of the NATURAL JOIN operation of these two table?
database relational-database natural-join
database relational-database natural-join
edited Nov 23 '18 at 21:23
nvogel
20.9k12962
asked Nov 23 '18 at 13:49
noobcodernoobcoder
498
edited Nov 23 '18 at 21:23
nvogel
20.9k12962
asked Nov 23 '18 at 13:49
noobcodernoobcoder
498
edited Nov 23 '18 at 21:23
nvogel
20.9k12962
edited Nov 23 '18 at 21:23
nvogel
20.9k12962
edited Nov 23 '18 at 21:23
nvogel
20.9k12962
20.9k12962
asked Nov 23 '18 at 13:49
noobcodernoobcoder
498
asked Nov 23 '18 at 13:49
noobcodernoobcoder
498
asked Nov 23 '18 at 13:49
noobcodernoobcoder
498
498
1
Please read & act on How to Ask, hits googling 'stackexchange homework' & the downvote arrow mouseover text. Quote the definition(s) you are using. Show/justify your work/reasonin following them. The first place you are stuck explain about why. PS Please use text, not images/links, for text (including code, tables & ERDs). Use a link/image only for convenience to supplement text and/or for what cannot be given in text. And never give a diagram without a legend/key. Make your post self-contained.
– philipxy
Nov 23 '18 at 19:44
1
What relations are those grids pictures of? You don't have an attribute name topping your columns & you don't have a single value for an attribute in a row. Suggest you rewrite them so you do. We can guess that the third column in each has attribute name X--is that right? We can guess that the value for an X attribute is the obvious relation made from the array of values & attributes C & D--is that right? (You are confusing something about attribute names & types.) Quote your textbook's definitions of "relation" & "natural join" (etc), give the relation values clearly & show work using them.
– philipxy
Nov 23 '18 at 19:53
1
PS If you made proper headings that were sets/lists of attribute names and just replaced the attribute values by xN, what would your answer be? PS If you were given those grids, how were you told to interpret them as relations? PS What does this have to do with your tag object-relational-model? PS "1NF" has no single meaning.
– philipxy
Nov 23 '18 at 20:00
add a comment |
1
Please read & act on How to Ask, hits googling 'stackexchange homework' & the downvote arrow mouseover text. Quote the definition(s) you are using. Show/justify your work/reasonin following them. The first place you are stuck explain about why. PS Please use text, not images/links, for text (including code, tables & ERDs). Use a link/image only for convenience to supplement text and/or for what cannot be given in text. And never give a diagram without a legend/key. Make your post self-contained.
– philipxy
Nov 23 '18 at 19:44
1
What relations are those grids pictures of? You don't have an attribute name topping your columns & you don't have a single value for an attribute in a row. Suggest you rewrite them so you do. We can guess that the third column in each has attribute name X--is that right? We can guess that the value for an X attribute is the obvious relation made from the array of values & attributes C & D--is that right? (You are confusing something about attribute names & types.) Quote your textbook's definitions of "relation" & "natural join" (etc), give the relation values clearly & show work using them.
– philipxy
Nov 23 '18 at 19:53
1
PS If you made proper headings that were sets/lists of attribute names and just replaced the attribute values by xN, what would your answer be? PS If you were given those grids, how were you told to interpret them as relations? PS What does this have to do with your tag object-relational-model? PS "1NF" has no single meaning.
– philipxy
Nov 23 '18 at 20:00
1
1
Please read & act on How to Ask, hits googling 'stackexchange homework' & the downvote arrow mouseover text. Quote the definition(s) you are using. Show/justify your work/reasonin following them. The first place you are stuck explain about why. PS Please use text, not images/links, for text (including code, tables & ERDs). Use a link/image only for convenience to supplement text and/or for what cannot be given in text. And never give a diagram without a legend/key. Make your post self-contained.
– philipxy
Nov 23 '18 at 19:44
Please read & act on How to Ask, hits googling 'stackexchange homework' & the downvote arrow mouseover text. Quote the definition(s) you are using. Show/justify your work/reasonin following them. The first place you are stuck explain about why. PS Please use text, not images/links, for text (including code, tables & ERDs). Use a link/image only for convenience to supplement text and/or for what cannot be given in text. And never give a diagram without a legend/key. Make your post self-contained.
– philipxy
Nov 23 '18 at 19:44
1
1
What relations are those grids pictures of? You don't have an attribute name topping your columns & you don't have a single value for an attribute in a row. Suggest you rewrite them so you do. We can guess that the third column in each has attribute name X--is that right? We can guess that the value for an X attribute is the obvious relation made from the array of values & attributes C & D--is that right? (You are confusing something about attribute names & types.) Quote your textbook's definitions of "relation" & "natural join" (etc), give the relation values clearly & show work using them.
– philipxy
Nov 23 '18 at 19:53
What relations are those grids pictures of? You don't have an attribute name topping your columns & you don't have a single value for an attribute in a row. Suggest you rewrite them so you do. We can guess that the third column in each has attribute name X--is that right? We can guess that the value for an X attribute is the obvious relation made from the array of values & attributes C & D--is that right? (You are confusing something about attribute names & types.) Quote your textbook's definitions of "relation" & "natural join" (etc), give the relation values clearly & show work using them.
– philipxy
Nov 23 '18 at 19:53
1
1
PS If you made proper headings that were sets/lists of attribute names and just replaced the attribute values by xN, what would your answer be? PS If you were given those grids, how were you told to interpret them as relations? PS What does this have to do with your tag object-relational-model? PS "1NF" has no single meaning.
– philipxy
Nov 23 '18 at 20:00
PS If you made proper headings that were sets/lists of attribute names and just replaced the attribute values by xN, what would your answer be? PS If you were given those grids, how were you told to interpret them as relations? PS What does this have to do with your tag object-relational-model? PS "1NF" has no single meaning.
– philipxy
Nov 23 '18 at 20:00
add a comment |
1 Answer
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active
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It is not exactly clear what your picture is supposed to represent. I'm going to assume that R1 is a relation with three attributes, A,B and X; R2 is a relation with three attributes, E,B and X.
The natural join would be a join where the values in B and X are equal in both R1 and R2. What type of attribute is X? If X is a relation-valued attribute and the columns labelled C and D represent the tuples in X then it seems that the relation values are different in each case. (X in R1 and X in R2 happen to have some of the same tuple values in common but the values of relation X are different in each case).
So the result of the natural join would be an empty relation with a heading of A,B,E,X but with zero tuples.
answered Nov 23 '18 at 20:34
nvogelnvogel
20.9k12962
Your picture is apt to confuse because it includes some sort of type info in column 3 of the heading when it doesn't for the others. If you're using some convention with a special layout for relation-valued attributes, you should say so. Even if that's maybe what the asker is consciously doing (in headings & values).
– philipxy
Nov 23 '18 at 20:47
add a comment |
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It is not exactly clear what your picture is supposed to represent. I'm going to assume that R1 is a relation with three attributes, A,B and X; R2 is a relation with three attributes, E,B and X.
The natural join would be a join where the values in B and X are equal in both R1 and R2. What type of attribute is X? If X is a relation-valued attribute and the columns labelled C and D represent the tuples in X then it seems that the relation values are different in each case. (X in R1 and X in R2 happen to have some of the same tuple values in common but the values of relation X are different in each case).
So the result of the natural join would be an empty relation with a heading of A,B,E,X but with zero tuples.
answered Nov 23 '18 at 20:34
nvogelnvogel
20.9k12962
Your picture is apt to confuse because it includes some sort of type info in column 3 of the heading when it doesn't for the others. If you're using some convention with a special layout for relation-valued attributes, you should say so. Even if that's maybe what the asker is consciously doing (in headings & values).
– philipxy
Nov 23 '18 at 20:47
add a comment |
It is not exactly clear what your picture is supposed to represent. I'm going to assume that R1 is a relation with three attributes, A,B and X; R2 is a relation with three attributes, E,B and X.
The natural join would be a join where the values in B and X are equal in both R1 and R2. What type of attribute is X? If X is a relation-valued attribute and the columns labelled C and D represent the tuples in X then it seems that the relation values are different in each case. (X in R1 and X in R2 happen to have some of the same tuple values in common but the values of relation X are different in each case).
So the result of the natural join would be an empty relation with a heading of A,B,E,X but with zero tuples.
answered Nov 23 '18 at 20:34
nvogelnvogel
20.9k12962
Your picture is apt to confuse because it includes some sort of type info in column 3 of the heading when it doesn't for the others. If you're using some convention with a special layout for relation-valued attributes, you should say so. Even if that's maybe what the asker is consciously doing (in headings & values).
– philipxy
Nov 23 '18 at 20:47
add a comment |
It is not exactly clear what your picture is supposed to represent. I'm going to assume that R1 is a relation with three attributes, A,B and X; R2 is a relation with three attributes, E,B and X.
The natural join would be a join where the values in B and X are equal in both R1 and R2. What type of attribute is X? If X is a relation-valued attribute and the columns labelled C and D represent the tuples in X then it seems that the relation values are different in each case. (X in R1 and X in R2 happen to have some of the same tuple values in common but the values of relation X are different in each case).
So the result of the natural join would be an empty relation with a heading of A,B,E,X but with zero tuples.
answered Nov 23 '18 at 20:34
nvogelnvogel
20.9k12962
It is not exactly clear what your picture is supposed to represent. I'm going to assume that R1 is a relation with three attributes, A,B and X; R2 is a relation with three attributes, E,B and X.
The natural join would be a join where the values in B and X are equal in both R1 and R2. What type of attribute is X? If X is a relation-valued attribute and the columns labelled C and D represent the tuples in X then it seems that the relation values are different in each case. (X in R1 and X in R2 happen to have some of the same tuple values in common but the values of relation X are different in each case).
So the result of the natural join would be an empty relation with a heading of A,B,E,X but with zero tuples.
answered Nov 23 '18 at 20:34
nvogelnvogel
20.9k12962
edited Nov 23 '18 at 21:16
answered Nov 23 '18 at 20:34
nvogelnvogel
20.9k12962
answered Nov 23 '18 at 20:34
nvogelnvogel
20.9k12962
answered Nov 23 '18 at 20:34
nvogelnvogel
20.9k12962
20.9k12962
Your picture is apt to confuse because it includes some sort of type info in column 3 of the heading when it doesn't for the others. If you're using some convention with a special layout for relation-valued attributes, you should say so. Even if that's maybe what the asker is consciously doing (in headings & values).
– philipxy
Nov 23 '18 at 20:47
add a comment |
Your picture is apt to confuse because it includes some sort of type info in column 3 of the heading when it doesn't for the others. If you're using some convention with a special layout for relation-valued attributes, you should say so. Even if that's maybe what the asker is consciously doing (in headings & values).
– philipxy
Nov 23 '18 at 20:47
Your picture is apt to confuse because it includes some sort of type info in column 3 of the heading when it doesn't for the others. If you're using some convention with a special layout for relation-valued attributes, you should say so. Even if that's maybe what the asker is consciously doing (in headings & values).
– philipxy
Nov 23 '18 at 20:47
Your picture is apt to confuse because it includes some sort of type info in column 3 of the heading when it doesn't for the others. If you're using some convention with a special layout for relation-valued attributes, you should say so. Even if that's maybe what the asker is consciously doing (in headings & values).
– philipxy
Nov 23 '18 at 20:47
add a comment |
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1
Please read & act on How to Ask, hits googling 'stackexchange homework' & the downvote arrow mouseover text. Quote the definition(s) you are using. Show/justify your work/reasonin following them. The first place you are stuck explain about why. PS Please use text, not images/links, for text (including code, tables & ERDs). Use a link/image only for convenience to supplement text and/or for what cannot be given in text. And never give a diagram without a legend/key. Make your post self-contained.
– philipxy
Nov 23 '18 at 19:44
1
What relations are those grids pictures of? You don't have an attribute name topping your columns & you don't have a single value for an attribute in a row. Suggest you rewrite them so you do. We can guess that the third column in each has attribute name X--is that right? We can guess that the value for an X attribute is the obvious relation made from the array of values & attributes C & D--is that right? (You are confusing something about attribute names & types.) Quote your textbook's definitions of "relation" & "natural join" (etc), give the relation values clearly & show work using them.
– philipxy
Nov 23 '18 at 19:53
1
PS If you made proper headings that were sets/lists of attribute names and just replaced the attribute values by xN, what would your answer be? PS If you were given those grids, how were you told to interpret them as relations? PS What does this have to do with your tag object-relational-model? PS "1NF" has no single meaning.
– philipxy
Nov 23 '18 at 20:00