• Inserted ACM-provided copyright, ISBN, and DOI.

• Added descriptive comments at top of file, and expanded some other comments. ...

• Commented out \todo macro.
• Updated copyright; added DOI and ISBN placeholders.
• Moved line break in title.
• Added CCS categories, and removed “relational model” from keywords.
• Removed commented out material for camera-ready version.
• Re-enabled column balancing.

• Final updates and changes prior to final re-submission.

• Updated SIG edge annotations to match latest knowledge. ...

• Rewrote part about trivial projection edges to refer instead to unique projection edges.
• Changed \T to \Type to avoid potential future macros clashes.
• Corrected definition of key edges.
• Added footnote about Miller’s mention of inclusion dependencies.
• Added more edges that lose annotations in S3 → S1 transformation.
• Removed conclusion paragraph about moving edges across bijective edges.

• Added keywords, and as a consequence: ...

– Rewrote and reformatted several paragraphs to resolve awkward page and column breaks.
    – Rearranged positioning of SIG figures.
• Fixed a couple of standalone operator expressions that should have been using a macro.
• Other minor phrasing tweaks.

• Minor phrasing, grammatical, and spelling tweaks.

• Minor grammatical and phrasing tweaks. ...

• Clarified removal of totality annotations.

• Added a Date citation. ...

• Minor phrasing and grammatical tweaks.

• Minor phrasing and grammatical tweaks. ...

• Added “constraints” to list of isomorphic items.
• Fixed format of subfigure captions.
• Flipped Figure 1 horizontally so that the functional path is more intuitive.

• Minor formatting, phrasing, and grammatical tweaks.

• Minor phrasing tweaks. ...

• Updated discussion of Date’s pragmatic approach.

• Minor phrasing tweaks. ...

• Rewrote sentence about update side effects.

• Corrected publication year of Date’s book.

• Minor tweak to conclusion.

• Rewrote conclusion. ...

• Other minor phrasing tweaks.

• Moved positions of Table 2 and Figure 5 to produce better layout.

• Various phrasing tweaks.

• Removed bold math in figure captions.

• Finished table of implied edges and rewrote description of S1 SIG construction to match.

• Shifted details of implied edges into a table.

• Rolled rewritten functional dependency constraints into the lists with the other rewritten constraints.

• Made consistent use of math mode for \LS and \NLS.

• Switched to newtxtext and newtxmath packages from txfonts. ...

• Removed no longer needed \!, as the spacing is now better.

• Switched to subfig package from subfigure. ...

• Switched to align environment instead of eqnarray.

• Fixed a couple of unconverted - to \setminus.

• Re-ordered and re-numbered rules. ...

• Added note about likelihood of S3 having different information capacity, due to not being able to map all the constraints from S0.

• Added macros to generate constraint numbers and constraint lists in standard format. ...

• Removed unnecessary \makeat* macros.
• Changed notation for propagated constraints.
• Minor tweaks to phrasing.

• Rephrased definition of key constraint edges.

• Rearranged position of some figures.

• Fixed horrible line breaking in math formula. ...

• Corrected annotations of copied projection edge between \TT{NLS} and \TSSNL.
• Added note about whether copied projection edges actually still count as projection edges.