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Per-column collation support

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This adds collation support for columns and domains, a COLLATE clause
to override it per expression, and B-tree index support.

Peter Eisentraut
reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch
This commit is contained in:
Peter Eisentraut
2011-02-08 23:04:18 +02:00
parent 1703f0e8da
commit 414c5a2ea6
156 changed files with 4519 additions and 582 deletions
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132
src/backend/parser/parse_coerce.c
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@ -16,6 +16,7 @@
#include "catalog/pg_cast.h"
#include "catalog/pg_class.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_inherits_fn.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
@ -216,6 +217,7 @@ coerce_type(ParseState *pstate, Node *node,
newcon->consttype = baseTypeId;
newcon->consttypmod = inputTypeMod;
newcon->constcollid = get_typcollation(newcon->consttype);
newcon->constlen = typeLen(targetType);
newcon->constbyval = typeByVal(targetType);
newcon->constisnull = con->constisnull;
@ -277,6 +279,14 @@ coerce_type(ParseState *pstate, Node *node,
if (result)
return result;
}
if (IsA(node, CollateClause))
{
CollateClause *cc = (CollateClause *) node;
cc->arg = (Expr *) coerce_type(pstate, (Node *) cc->arg, inputTypeId, targetTypeId, targetTypeMod,
ccontext, cformat, location);
return (Node *) cc;
}
pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext,
&funcId);
if (pathtype != COERCION_PATH_NONE)
@ -718,6 +728,7 @@ build_coercion_expression(Node *node,
FuncExpr *fexpr;
List *args;
Const *cons;
Oid collation;
Assert(OidIsValid(funcId));
@ -749,7 +760,9 @@ build_coercion_expression(Node *node,
args = lappend(args, cons);
}
fexpr = makeFuncExpr(funcId, targetTypeId, args, cformat);
collation = coercion_expression_result_collation(targetTypeId, node);
fexpr = makeFuncExpr(funcId, targetTypeId, args, collation, cformat);
fexpr->location = location;
return (Node *) fexpr;
}
@ -2081,3 +2094,120 @@ typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId)
return result;
}
/*
* select_common_collation() -- determine one collation to apply for
* an expression node, for evaluating the expression itself or to
* label the result of the expression node.
*
* none_ok means that it is permitted to return "no" collation. It is
* then not possible to sort the result value of whatever expression
* is applying this. none_ok = true reflects the rules of SQL
* standard clause "Result of data type combinations", none_ok = false
* reflects the rules of clause "Collation determination" (in some
* cases invoked via "Grouping operations").
*/
Oid
select_common_collation(ParseState *pstate, List *exprs, bool none_ok)
{
ListCell *lc;
/*
* Check if there are any explicit collation derivations. If so,
* they must all be the same.
*/
foreach(lc, exprs)
{
Node *pexpr = (Node *) lfirst(lc);
Oid pcoll = exprCollation(pexpr);
bool pexplicit = IsA(pexpr, CollateClause);
if (pcoll && pexplicit)
{
ListCell *lc2;
for_each_cell(lc2, lnext(lc))
{
Node *nexpr = (Node *) lfirst(lc2);
Oid ncoll = exprCollation(nexpr);
bool nexplicit = IsA(nexpr, CollateClause);
if (!ncoll || !nexplicit)
continue;
if (ncoll != pcoll)
ereport(ERROR,
(errcode(ERRCODE_COLLATION_MISMATCH),
errmsg("collation mismatch between explicit collations \"%s\" and \"%s\"",
get_collation_name(pcoll),
get_collation_name(ncoll)),
parser_errposition(pstate, exprLocation(nexpr))));
}
return pcoll;
}
}
/*
* Check if there are any implicit collation derivations.
*/
foreach(lc, exprs)
{
Node *pexpr = (Node *) lfirst(lc);
Oid pcoll = exprCollation(pexpr);
if (pcoll && pcoll != DEFAULT_COLLATION_OID)
{
ListCell *lc2;
for_each_cell(lc2, lnext(lc))
{
Node *nexpr = (Node *) lfirst(lc2);
Oid ncoll = exprCollation(nexpr);
if (!ncoll || ncoll == DEFAULT_COLLATION_OID)
continue;
if (ncoll != pcoll)
{
if (none_ok)
return InvalidOid;
ereport(ERROR,
(errcode(ERRCODE_COLLATION_MISMATCH),
errmsg("collation mismatch between implicit collations \"%s\" and \"%s\"",
get_collation_name(pcoll),
get_collation_name(ncoll)),
errhint("You can override the collation by applying the COLLATE clause to one or both expressions."),
parser_errposition(pstate, exprLocation(nexpr))));
}
}
return pcoll;
}
}
foreach(lc, exprs)
{
Node *pexpr = (Node *) lfirst(lc);
Oid pcoll = exprCollation(pexpr);
if (pcoll == DEFAULT_COLLATION_OID)
{
ListCell *lc2;
for_each_cell(lc2, lnext(lc))
{
Node *nexpr = (Node *) lfirst(lc2);
Oid ncoll = exprCollation(nexpr);
if (ncoll != pcoll)
break;
}
return pcoll;
}
}
/*
* Else use default
*/
return InvalidOid;
}