Mercurial > urweb
changeset 1627:5c1f10cdac63
New 't.*' notation for SELECT
| author | Adam Chlipala <adam@chlipala.net> |
|---|---|
| date | Sat, 03 Dec 2011 17:07:34 -0500 |
| parents | 07eed8386f07 |
| children | 3621f486ce72 |
| files | doc/manual.tex src/urweb.grm tests/selclause.ur tests/selclause.urp |
| diffstat | 4 files changed, 67 insertions(+), 9 deletions(-) [+] |
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--- a/doc/manual.tex Sat Dec 03 16:39:45 2011 -0500 +++ b/doc/manual.tex Sat Dec 03 17:07:34 2011 -0500 @@ -2128,6 +2128,7 @@ &&& p,^+ & \textrm{particular columns} \\ \textrm{Pre-projections} & p &::=& t.f & \textrm{one column from a table} \\ &&& t.\{\{c\}\} & \textrm{a record of columns from a table (of kind $\{\mt{Type}\}$)} \\ + &&& t.* & \textrm{all columns from a table} \\ &&& E \; [\mt{AS} \; f] & \textrm{expression column} \\ \textrm{Table names} & t &::=& x & \textrm{constant table name (automatically capitalized)} \\ &&& X & \textrm{constant table name} \\
--- a/src/urweb.grm Sat Dec 03 16:39:45 2011 -0500 +++ b/src/urweb.grm Sat Dec 03 17:07:34 2011 -0500 @@ -44,6 +44,7 @@ Field of con * con | Exp of con option * exp | Fields of con * con + | StarFields of con datatype select = Star @@ -65,6 +66,11 @@ | CVar (_, x) => x | _ => "?" +datatype tableMode = + Unknown + | Everything + | Selective of con + fun amend_select loc (si, (count, tabs, exps)) = case si of Field (tx, fx) => @@ -73,7 +79,15 @@ val (tabs, found) = ListUtil.foldlMap (fn ((tx', c'), found) => if eqTnames (tx, tx') then - ((tx', (CConcat (c, c'), loc)), true) + case c' of + Everything => + (ErrorMsg.errorAt loc + "Mixing specific-field and '*' selection of fields from same table"; + ((tx', c'), found)) + | Unknown => + ((tx', Selective c), true) + | Selective c' => + ((tx', Selective (CConcat (c, c'), loc)), true) else ((tx', c'), found)) false tabs @@ -89,7 +103,15 @@ let val (tabs, found) = ListUtil.foldlMap (fn ((tx', c'), found) => if eqTnames (tx, tx') then - ((tx', (CConcat (fs, c'), loc)), true) + case c' of + Everything => + (ErrorMsg.errorAt loc + "Mixing specific-field and '*' selection of fields from same table"; + ((tx', c'), found)) + | Selective c' => + ((tx', Selective (CConcat (fs, c'), loc)), true) + | Unknown => + ((tx', Selective fs), true) else ((tx', c'), found)) false tabs @@ -101,6 +123,17 @@ (count, tabs, exps) end + | StarFields tx => + if List.exists (fn (tx', c') => eqTnames (tx, tx') andalso case c' of + Unknown => false + | _ => true) tabs then + (ErrorMsg.errorAt loc "Selection with '*' from table already mentioned in same SELECT clause"; + (count, tabs, exps)) + else if List.all (fn (tx', c') => not (eqTnames (tx, tx'))) tabs then + (ErrorMsg.errorAt loc "Select of all fields from unbound table"; + (count, tabs, exps)) + else + (count, map (fn (tx', c') => (tx', if eqTnames (tx, tx') then Everything else c')) tabs, exps) | Exp (SOME c, e) => (count, tabs, (c, e) :: exps) | Exp (NONE, e) => (count+1, tabs, ((CName (Int.toString count), loc), e) :: exps) @@ -1560,18 +1593,31 @@ []) | Items sis => let - val tabs = map (fn nm => (nm, (CRecord [], loc))) (#1 tables) + val tabs = map (fn nm => (nm, Unknown)) (#1 tables) val (_, tabs, exps) = foldl (amend_select loc) (1, tabs, []) sis - val empties = List.mapPartial (fn (nm, (CRecord [], _)) => - SOME nm - | _ => NONE) tabs + val empties = List.mapPartial (fn (nm, c) => + case c of + Unknown => SOME nm + | Selective (CRecord [], _) => SOME nm + | _ => NONE) tabs in (empties, map (fn (nm, c) => (nm, - (CTuple [c, - (CWild (KRecord (KType, loc), loc), - loc)], loc))) tabs, + case c of + Everything => + (CTuple [(CWild (KRecord (KType, loc), loc), loc), + (CRecord [], loc)], loc) + | _ => + let + val c = case c of + Selective c => c + | _ => (CRecord [], loc) + in + (CTuple [c, + (CWild (KRecord (KType, loc), loc), + loc)], loc) + end)) tabs, exps) end @@ -1770,6 +1816,7 @@ | sqlexp (Exp (NONE, sqlexp)) | sqlexp AS fident (Exp (SOME fident, sqlexp)) | tident DOT LBRACE LBRACE cexp RBRACE RBRACE (Fields (tident, cexp)) + | tident DOT STAR (StarFields tident) selis : seli ([seli]) | seli COMMA selis (seli :: selis)
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/tests/selclause.ur Sat Dec 03 17:07:34 2011 -0500 @@ -0,0 +1,6 @@ +table t : { A : int, B : string, C : float } +table u : { D : int, E : string, F : float } + +val q : transaction (list {T : { A : int, B : string, C : float}, U : { D : int }, X : string }) = + queryL (SELECT t.*, u.D, 'hi' AS X + FROM t, u)