4 ms·

Not the result set, the rows of the result set.

icedchai 9y ago
Unless there is an "order by" clause, the order of rows in the result set is undefined and non-deterministic from query to query.
- djrobstep 9y ago
  As I said: > Not the result set, the rows of the result set. Each row is a mapping with ordered keys.
  - icedchai 9y ago
    Perhaps you are confused and mean "columns"? ("Rows of the result set" is what I was referring to.) A result set has rows, which are not in a deterministic order unless an "order by" is provided. Each row has columns. The columns are in order, obviously.
    - djrobstep 9y ago
      Perhaps you are confused and think I'm talking about the ordering of the result set. I said that database query result rows are made up of ordered dictionaries. I didn't mention ordering of the result set. Happy to keep repeating this as many times as necessary.
      - icedchai 9y ago
        ok. We're actually saying the same thing, just in different words.
jsjohnst 9y ago
Do you mean the columns of the row?
- djrobstep 9y ago
  No, I mean the rows. Each row is semantically an ordered mapping.
  - jsjohnst 9y ago
    Shouldn’t the collection of rows be a set or list, not a dictionary? That said, you disagreed with my question then went on to show my question was on point. The “rows themself” being an ordered map means you are referring to the columns, the order being set by the SELECT clause or table definition order (in case of wildcard). That said, I personally feel iterating over table columns in that way to be a “bad code smell”. Not saying it’s bad in all cases, but generally it’s an anti-pattern to me.
    - empthought 9y ago
      Order-significance is exactly how the relational model was defined in the beginning "An array which represents an n-ary relation R has the following properties: 1. Each row represents an n-tuple of R. 2. The ordering of rows is immaterial. 3. All rows are distinct. 4. The ordering of columns is significant -- it corresponds to the ordering S1, S2, ..., Sn of the domains on which R is defined (see, however, remarks below on domain-ordered and domain-unordered relations). 5. The significance of each column is partially conveyed by labeling it with the name of the corresponding domain." -- A relational model of data for large shared data banks[1] [1]: https://cs.uwaterloo.ca/~david/cs848s14/codd-relational.pdf https://cs.uwaterloo.ca/~david/cs848s14/codd-relational.pdf
    - djrobstep 9y ago
      > Shouldn’t the collection of rows be a set or list, not a dictionary? I didn't mention the collection of rows, I mentioned the rows themselves. > The “rows themself” being an ordered map means you are referring to the columns No, it means I'm referring to the rows themselves. The rows themselves are each ordered mappings. Hope this helps to clarify things. Happy to keep repeating this as many times as necessary.
    - dragonwriter 9y ago

Unless there is an "order by" clause, the order of rows in the result set is undefined and non-deterministic from query to query.

djrobstep 9y ago
As I said: > Not the result set, the rows of the result set. Each row is a mapping with ordered keys.
- icedchai 9y ago
  Perhaps you are confused and mean "columns"? ("Rows of the result set" is what I was referring to.) A result set has rows, which are not in a deterministic order unless an "order by" is provided. Each row has columns. The columns are in order, obviously.
  - djrobstep 9y ago
    Perhaps you are confused and think I'm talking about the ordering of the result set. I said that database query result rows are made up of ordered dictionaries. I didn't mention ordering of the result set. Happy to keep repeating this as many times as necessary.
    - icedchai 9y ago
      ok. We're actually saying the same thing, just in different words.

jsjohnst 9y ago

Do you mean the columns of the row?

djrobstep 9y ago
No, I mean the rows. Each row is semantically an ordered mapping.
- jsjohnst 9y ago
  Shouldn’t the collection of rows be a set or list, not a dictionary? That said, you disagreed with my question then went on to show my question was on point. The “rows themself” being an ordered map means you are referring to the columns, the order being set by the SELECT clause or table definition order (in case of wildcard). That said, I personally feel iterating over table columns in that way to be a “bad code smell”. Not saying it’s bad in all cases, but generally it’s an anti-pattern to me.
  - empthought 9y ago
    Order-significance is exactly how the relational model was defined in the beginning "An array which represents an n-ary relation R has the following properties: 1. Each row represents an n-tuple of R. 2. The ordering of rows is immaterial. 3. All rows are distinct. 4. The ordering of columns is significant -- it corresponds to the ordering S1, S2, ..., Sn of the domains on which R is defined (see, however, remarks below on domain-ordered and domain-unordered relations). 5. The significance of each column is partially conveyed by labeling it with the name of the corresponding domain." -- A relational model of data for large shared data banks[1] [1]: https://cs.uwaterloo.ca/~david/cs848s14/codd-relational.pdf https://cs.uwaterloo.ca/~david/cs848s14/codd-relational.pdf
  - djrobstep 9y ago
    > Shouldn’t the collection of rows be a set or list, not a dictionary? I didn't mention the collection of rows, I mentioned the rows themselves. > The “rows themself” being an ordered map means you are referring to the columns No, it means I'm referring to the rows themselves. The rows themselves are each ordered mappings. Hope this helps to clarify things. Happy to keep repeating this as many times as necessary.
  - dragonwriter 9y ago