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postgres/src/backend/parser/analyze.c
Tom Lane f68e11f373 Implement subselects in target lists. Also, relax requirement that 
subselects can only appear on the righthand side of a binary operator.
That's still true for quantified predicates like x = ANY (SELECT ...),
but a subselect that delivers a single result can now appear anywhere
in an expression.  This is implemented by changing EXPR_SUBLINK sublinks
to represent just the (SELECT ...) expression, without any 'left hand
side' or combining operator --- so they're now more like EXISTS_SUBLINK.
To handle the case of '(x, y, z) = (SELECT ...)', I added a new sublink
type MULTIEXPR_SUBLINK, which acts just like EXPR_SUBLINK used to.
But the grammar will only generate one for a multiple-left-hand-side
row expression.
1999-11-15 02:00:15 +00:00

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/*-------------------------------------------------------------------------
*
* analyze.c
* transform the parse tree into a query tree
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: analyze.c,v 1.124 1999/11/15 02:00:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "parse.h"
#include "parser/analyze.h"
#include "parser/parse_agg.h"
#include "parser/parse_clause.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "utils/builtins.h"
static Query *transformStmt(ParseState *pstate, Node *stmt);
static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt);
static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
static Query *transformExtendStmt(ParseState *pstate, ExtendStmt *stmt);
static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt);
static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
static Query *transformCursorStmt(ParseState *pstate, SelectStmt *stmt);
static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt);
static void transformForUpdate(Query *qry, List *forUpdate);
void CheckSelectForUpdate(Query *qry);
/* kluge to return extra info from transformCreateStmt() */
static List *extras_before;
static List *extras_after;
/*
* parse_analyze -
* analyze a list of parse trees and transform them if necessary.
*
* Returns a list of transformed parse trees. Optimizable statements are
* all transformed to Query while the rest stays the same.
*
*/
List *
parse_analyze(List *pl, ParseState *parentParseState)
{
List *result = NIL;
ParseState *pstate;
Query *parsetree;
while (pl != NIL)
{
extras_before = extras_after = NIL;
pstate = make_parsestate(parentParseState);
parsetree = transformStmt(pstate, lfirst(pl));
if (pstate->p_target_relation != NULL)
heap_close(pstate->p_target_relation, AccessShareLock);
pstate->p_target_relation = NULL;
pstate->p_target_rangetblentry = NULL;
while (extras_before != NIL)
{
result = lappend(result,
transformStmt(pstate, lfirst(extras_before)));
if (pstate->p_target_relation != NULL)
heap_close(pstate->p_target_relation, AccessShareLock);
pstate->p_target_relation = NULL;
pstate->p_target_rangetblentry = NULL;
extras_before = lnext(extras_before);
}
result = lappend(result, parsetree);
while (extras_after != NIL)
{
result = lappend(result,
transformStmt(pstate, lfirst(extras_after)));
if (pstate->p_target_relation != NULL)
heap_close(pstate->p_target_relation, AccessShareLock);
pstate->p_target_relation = NULL;
pstate->p_target_rangetblentry = NULL;
extras_after = lnext(extras_after);
}
pfree(pstate);
pl = lnext(pl);
}
return result;
}
/*
* transformStmt -
* transform a Parse tree. If it is an optimizable statement, turn it
* into a Query tree.
*/
static Query *
transformStmt(ParseState *pstate, Node *parseTree)
{
Query *result = NULL;
switch (nodeTag(parseTree))
{
/*------------------------
* Non-optimizable statements
*------------------------
*/
case T_CreateStmt:
result = transformCreateStmt(pstate, (CreateStmt *) parseTree);
break;
case T_IndexStmt:
result = transformIndexStmt(pstate, (IndexStmt *) parseTree);
break;
case T_ExtendStmt:
result = transformExtendStmt(pstate, (ExtendStmt *) parseTree);
break;
case T_RuleStmt:
result = transformRuleStmt(pstate, (RuleStmt *) parseTree);
break;
case T_ViewStmt:
{
ViewStmt *n = (ViewStmt *) parseTree;
n->query = (Query *) transformStmt(pstate, (Node *) n->query);
result = makeNode(Query);
result->commandType = CMD_UTILITY;
result->utilityStmt = (Node *) n;
}
break;
case T_VacuumStmt:
{
MemoryContext oldcontext;
/*
* make sure that this Query is allocated in TopMemory
* context because vacuum spans transactions and we don't
* want to lose the vacuum Query due to end-of-transaction
* free'ing
*/
oldcontext = MemoryContextSwitchTo(TopMemoryContext);
result = makeNode(Query);
result->commandType = CMD_UTILITY;
result->utilityStmt = (Node *) parseTree;
MemoryContextSwitchTo(oldcontext);
}
break;
case T_ExplainStmt:
{
ExplainStmt *n = (ExplainStmt *) parseTree;
result = makeNode(Query);
result->commandType = CMD_UTILITY;
n->query = transformStmt(pstate, (Node *) n->query);
result->utilityStmt = (Node *) parseTree;
}
break;
/*------------------------
* Optimizable statements
*------------------------
*/
case T_InsertStmt:
result = transformInsertStmt(pstate, (InsertStmt *) parseTree);
break;
case T_DeleteStmt:
result = transformDeleteStmt(pstate, (DeleteStmt *) parseTree);
break;
case T_UpdateStmt:
result = transformUpdateStmt(pstate, (UpdateStmt *) parseTree);
break;
case T_SelectStmt:
if (!((SelectStmt *) parseTree)->portalname)
{
result = transformSelectStmt(pstate, (SelectStmt *) parseTree);
result->limitOffset = ((SelectStmt *) parseTree)->limitOffset;
result->limitCount = ((SelectStmt *) parseTree)->limitCount;
}
else
result = transformCursorStmt(pstate, (SelectStmt *) parseTree);
break;
default:
/*
* other statments don't require any transformation-- just
* return the original parsetree, yea!
*/
result = makeNode(Query);
result->commandType = CMD_UTILITY;
result->utilityStmt = (Node *) parseTree;
break;
}
return result;
}
/*
* transformDeleteStmt -
* transforms a Delete Statement
*/
static Query *
transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
{
Query *qry = makeNode(Query);
qry->commandType = CMD_DELETE;
/* set up a range table */
makeRangeTable(pstate, NULL, NULL);
setTargetTable(pstate, stmt->relname);
qry->uniqueFlag = NULL;
/* fix where clause */
qry->qual = transformWhereClause(pstate, stmt->whereClause, NULL);
qry->rtable = pstate->p_rtable;
qry->resultRelation = refnameRangeTablePosn(pstate, stmt->relname, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs)
parseCheckAggregates(pstate, qry);
return (Query *) qry;
}
/*
* transformInsertStmt -
* transform an Insert Statement
*/
static Query *
transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
{
Query *qry = makeNode(Query);
Node *fromQual;
List *icolumns;
List *attrnos;
List *attnos;
int numuseratts;
List *tl;
TupleDesc rd_att;
qry->commandType = CMD_INSERT;
pstate->p_is_insert = true;
/*----------
* Initial processing steps are just like SELECT, which should not
* be surprising, since we may be handling an INSERT ... SELECT.
* It is important that we finish processing all the SELECT subclauses
* before we start doing any INSERT-specific processing; otherwise
* the behavior of SELECT within INSERT might be different from a
* stand-alone SELECT. (Indeed, Postgres up through 6.5 had bugs of
* just that nature...)
*----------
*/
/* set up a range table --- note INSERT target is not in it yet */
makeRangeTable(pstate, stmt->fromClause, &fromQual);
qry->uniqueFlag = stmt->unique;
qry->targetList = transformTargetList(pstate, stmt->targetList);
qry->qual = transformWhereClause(pstate, stmt->whereClause, fromQual);
/* Initial processing of HAVING clause is just like WHERE clause.
* Additional work will be done in optimizer/plan/planner.c.
*/
qry->havingQual = transformWhereClause(pstate, stmt->havingClause, NULL);
qry->groupClause = transformGroupClause(pstate,
stmt->groupClause,
qry->targetList);
/* An InsertStmt has no sortClause, but we still call
* transformSortClause because it also handles uniqueFlag.
*/
qry->sortClause = transformSortClause(pstate,
NIL,
qry->targetList,
qry->uniqueFlag);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
parseCheckAggregates(pstate, qry);
/*
* The INSERT INTO ... SELECT ... could have a UNION in child, so
* unionClause may be false
*/
qry->unionall = stmt->unionall;
/*
* Just hand through the unionClause and intersectClause. We will
* handle it in the function Except_Intersect_Rewrite()
*/
qry->unionClause = stmt->unionClause;
qry->intersectClause = stmt->intersectClause;
/*
* Now we are done with SELECT-like processing, and can get on with
* transforming the target list to match the INSERT target columns.
*
* In particular, it's time to add the INSERT target to the rangetable.
* (We didn't want it there until now since it shouldn't be visible in
* the SELECT part.)
*/
setTargetTable(pstate, stmt->relname);
/* now the range table will not change */
qry->rtable = pstate->p_rtable;
qry->resultRelation = refnameRangeTablePosn(pstate, stmt->relname, NULL);
/* Prepare to assign non-conflicting resnos to resjunk attributes */
if (pstate->p_last_resno <= pstate->p_target_relation->rd_rel->relnatts)
pstate->p_last_resno = pstate->p_target_relation->rd_rel->relnatts + 1;
/* Validate stmt->cols list, or build default list if no list given */
icolumns = checkInsertTargets(pstate, stmt->cols, &attrnos);
/* Prepare non-junk columns for assignment to target table */
numuseratts = 0;
attnos = attrnos;
foreach(tl, qry->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
Resdom *resnode = tle->resdom;
Ident *id;
if (resnode->resjunk)
{
/* Resjunk nodes need no additional processing, but be sure they
* have names and resnos that do not match any target columns;
* else rewriter or planner might get confused.
*/
resnode->resname = "?resjunk?";
resnode->resno = (AttrNumber) pstate->p_last_resno++;
continue;
}
if (icolumns == NIL || attnos == NIL)
elog(ERROR, "INSERT has more expressions than target columns");
id = (Ident *) lfirst(icolumns);
updateTargetListEntry(pstate, tle, id->name, lfirsti(attnos),
id->indirection);
numuseratts++;
icolumns = lnext(icolumns);
attnos = lnext(attnos);
}
/*
* It is possible that the targetlist has fewer entries than were in
* the columns list. We do not consider this an error (perhaps we
* should, if the columns list was explictly given?). We must truncate
* the attrnos list to only include the attrs actually provided,
* else we will fail to apply defaults for them below.
*/
if (icolumns != NIL)
attrnos = ltruncate(numuseratts, attrnos);
/*
* Add targetlist items to assign DEFAULT values to any columns that
* have defaults and were not assigned to by the user.
*
* XXX wouldn't it make more sense to do this further downstream,
* after the rule rewriter?
*/
rd_att = pstate->p_target_relation->rd_att;
if (rd_att->constr && rd_att->constr->num_defval > 0)
{
Form_pg_attribute *att = rd_att->attrs;
AttrDefault *defval = rd_att->constr->defval;
int ndef = rd_att->constr->num_defval;
while (--ndef >= 0)
{
AttrNumber attrno = defval[ndef].adnum;
Form_pg_attribute thisatt = att[attrno - 1];
TargetEntry *te;
if (intMember((int) attrno, attrnos))
continue; /* there was a user-specified value */
/*
* No user-supplied value, so add a targetentry with DEFAULT expr
* and correct data for the target column.
*/
te = makeTargetEntry(
makeResdom(attrno,
thisatt->atttypid,
thisatt->atttypmod,
pstrdup(NameStr(thisatt->attname)),
0, 0, false),
stringToNode(defval[ndef].adbin));
qry->targetList = lappend(qry->targetList, te);
/*
* Make sure the value is coerced to the target column type
* (might not be right type if it's not a constant!)
*/
updateTargetListEntry(pstate, te, te->resdom->resname, attrno,
NIL);
}
}
if (stmt->forUpdate != NULL)
transformForUpdate(qry, stmt->forUpdate);
/* in case of subselects in default clauses... */
qry->hasSubLinks = pstate->p_hasSubLinks;
return (Query *) qry;
}
/*
* makeObjectName()
*
* Create a name for an implicitly created index, sequence, constraint, etc.
*
* The parameters are: the original table name, the original field name, and
* a "type" string (such as "seq" or "pkey"). The field name and/or type
* can be NULL if not relevant.
*
* The result is a palloc'd string.
*
* The basic result we want is "name1_name2_type", omitting "_name2" or
* "_type" when those parameters are NULL. However, we must generate
* a name with less than NAMEDATALEN characters! So, we truncate one or
* both names if necessary to make a short-enough string. The type part
* is never truncated (so it had better be reasonably short).
*
* To reduce the probability of collisions, we might someday add more
* smarts to this routine, like including some "hash" characters computed
* from the truncated characters. Currently it seems best to keep it simple,
* so that the generated names are easily predictable by a person.
*/
static char *
makeObjectName(char *name1, char *name2, char *typename)
{
char *name;
int overhead = 0; /* chars needed for type and underscores */
int availchars; /* chars available for name(s) */
int name1chars; /* chars allocated to name1 */
int name2chars; /* chars allocated to name2 */
int ndx;
name1chars = strlen(name1);
if (name2)
{
name2chars = strlen(name2);
overhead++; /* allow for separating underscore */
}
else
name2chars = 0;
if (typename)
overhead += strlen(typename) + 1;
availchars = NAMEDATALEN-1 - overhead;
/* If we must truncate, preferentially truncate the longer name.
* This logic could be expressed without a loop, but it's simple and
* obvious as a loop.
*/
while (name1chars + name2chars > availchars)
{
if (name1chars > name2chars)
name1chars--;
else
name2chars--;
}
/* Now construct the string using the chosen lengths */
name = palloc(name1chars + name2chars + overhead + 1);
strncpy(name, name1, name1chars);
ndx = name1chars;
if (name2)
{
name[ndx++] = '_';
strncpy(name+ndx, name2, name2chars);
ndx += name2chars;
}
if (typename)
{
name[ndx++] = '_';
strcpy(name+ndx, typename);
}
else
name[ndx] = '\0';
return name;
}
static char *
CreateIndexName(char *table_name, char *column_name, char *label, List *indices)
{
int pass = 0;
char *iname = NULL;
List *ilist;
char typename[NAMEDATALEN];
/* The type name for makeObjectName is label, or labelN if that's
* necessary to prevent collisions among multiple indexes for the same
* table. Note there is no check for collisions with already-existing
* indexes; this ought to be rethought someday.
*/
strcpy(typename, label);
for (;;)
{
iname = makeObjectName(table_name, column_name, typename);
foreach(ilist, indices)
{
IndexStmt *index = lfirst(ilist);
if (strcasecmp(iname, index->idxname) == 0)
break;
}
/* ran through entire list? then no name conflict found so done */
if (ilist == NIL)
break;
/* the last one conflicted, so try a new name component */
pfree(iname);
sprintf(typename, "%s%d", label, ++pass);
}
return iname;
}
/*
* transformCreateStmt -
* transforms the "create table" statement
* SQL92 allows constraints to be scattered all over, so thumb through
* the columns and collect all constraints into one place.
* If there are any implied indices (e.g. UNIQUE or PRIMARY KEY)
* then expand those into multiple IndexStmt blocks.
* - thomas 1997-12-02
*/
static Query *
transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
{
Query *q;
List *elements;
Node *element;
List *columns;
List *dlist;
ColumnDef *column;
List *constraints,
*clist;
Constraint *constraint;
List *keys;
Ident *key;
List *blist = NIL; /* "before list" of things to do before
* creating the table */
List *ilist = NIL; /* "index list" of things to do after
* creating the table */
IndexStmt *index,
*pkey = NULL;
IndexElem *iparam;
q = makeNode(Query);
q->commandType = CMD_UTILITY;
constraints = stmt->constraints;
columns = NIL;
dlist = NIL;
/*
* Run through each primary element in the table creation clause
*/
foreach(elements, stmt->tableElts)
{
element = lfirst(elements);
switch (nodeTag(element))
{
case T_ColumnDef:
column = (ColumnDef *) element;
columns = lappend(columns, column);
/* Special case SERIAL type? */
if (column->is_sequence)
{
char *sname;
char *qstring;
A_Const *snamenode;
FuncCall *funccallnode;
CreateSeqStmt *sequence;
sname = makeObjectName(stmt->relname, column->colname,
"seq");
/*
* Create an expression tree representing the function
* call nextval('"sequencename"')
*/
qstring = palloc(strlen(sname) + 2 + 1);
sprintf(qstring, "\"%s\"", sname);
snamenode = makeNode(A_Const);
snamenode->val.type = T_String;
snamenode->val.val.str = qstring;
funccallnode = makeNode(FuncCall);
funccallnode->funcname = "nextval";
funccallnode->args = lcons(snamenode, NIL);
constraint = makeNode(Constraint);
constraint->contype = CONSTR_DEFAULT;
constraint->name = sname;
constraint->raw_expr = (Node *) funccallnode;
constraint->cooked_expr = NULL;
constraint->keys = NULL;
column->constraints = lappend(column->constraints, constraint);
constraint = makeNode(Constraint);
constraint->contype = CONSTR_UNIQUE;
constraint->name = makeObjectName(stmt->relname,
column->colname,
"key");
column->constraints = lappend(column->constraints, constraint);
sequence = makeNode(CreateSeqStmt);
sequence->seqname = pstrdup(sname);
sequence->options = NIL;
elog(NOTICE, "CREATE TABLE will create implicit sequence '%s' for SERIAL column '%s.%s'",
sequence->seqname, stmt->relname, column->colname);
blist = lcons(sequence, NIL);
}
/* Process column constraints, if any... */
foreach(clist, column->constraints)
{
constraint = lfirst(clist);
switch (constraint->contype)
{
case CONSTR_NULL:
/*
* We should mark this explicitly, so we
* can tell if NULL and NOT NULL are both
* specified
*/
if (column->is_not_null)
elog(ERROR, "CREATE TABLE/(NOT) NULL conflicting declaration"
" for '%s.%s'", stmt->relname, column->colname);
column->is_not_null = FALSE;
break;
case CONSTR_NOTNULL:
if (column->is_not_null)
elog(ERROR, "CREATE TABLE/NOT NULL already specified"
" for '%s.%s'", stmt->relname, column->colname);
column->is_not_null = TRUE;
break;
case CONSTR_DEFAULT:
if (column->raw_default != NULL)
elog(ERROR, "CREATE TABLE/DEFAULT multiple values specified"
" for '%s.%s'", stmt->relname, column->colname);
column->raw_default = constraint->raw_expr;
Assert(constraint->cooked_expr == NULL);
break;
case CONSTR_PRIMARY:
if (constraint->name == NULL)
constraint->name = makeObjectName(stmt->relname, NULL, "pkey");
if (constraint->keys == NIL)
constraint->keys = lappend(constraint->keys, column);
dlist = lappend(dlist, constraint);
break;
case CONSTR_UNIQUE:
if (constraint->name == NULL)
constraint->name = makeObjectName(stmt->relname, column->colname, "key");
if (constraint->keys == NIL)
constraint->keys = lappend(constraint->keys, column);
dlist = lappend(dlist, constraint);
break;
case CONSTR_CHECK:
if (constraint->name == NULL)
constraint->name = makeObjectName(stmt->relname, column->colname, NULL);
constraints = lappend(constraints, constraint);
break;
default:
elog(ERROR, "parser: unrecognized constraint (internal error)", NULL);
break;
}
}
break;
case T_Constraint:
constraint = (Constraint *) element;
switch (constraint->contype)
{
case CONSTR_PRIMARY:
if (constraint->name == NULL)
constraint->name = makeObjectName(stmt->relname, NULL, "pkey");
dlist = lappend(dlist, constraint);
break;
case CONSTR_UNIQUE:
dlist = lappend(dlist, constraint);
break;
case CONSTR_CHECK:
constraints = lappend(constraints, constraint);
break;
case CONSTR_NOTNULL:
case CONSTR_DEFAULT:
elog(ERROR, "parser: illegal context for constraint (internal error)");
break;
default:
elog(ERROR, "parser: unrecognized constraint (internal error)");
break;
}
break;
default:
elog(ERROR, "parser: unrecognized node (internal error)");
}
}
stmt->tableElts = columns;
stmt->constraints = constraints;
/* Now run through the "deferred list" to complete the query transformation.
* For PRIMARY KEYs, mark each column as NOT NULL and create an index.
* For UNIQUE, create an index as for PRIMARY KEYS, but do not insist on NOT NULL.
*
* Note that this code does not currently look for all possible redundant cases
* and either ignore or stop with warning. The create might fail later when
* names for indices turn out to be duplicated, or a user might have specified
* extra useless indices which might hurt performance. - thomas 1997-12-08
*/
while (dlist != NIL)
{
constraint = lfirst(dlist);
Assert(nodeTag(constraint) == T_Constraint);
Assert((constraint->contype == CONSTR_PRIMARY)
|| (constraint->contype == CONSTR_UNIQUE));
index = makeNode(IndexStmt);
index->unique = TRUE;
index->primary = (constraint->contype == CONSTR_PRIMARY ? TRUE : FALSE);
if (index->primary)
{
if (pkey != NULL)
elog(ERROR, "CREATE TABLE/PRIMARY KEY multiple primary keys"
" for table '%s' are not allowed", stmt->relname);
pkey = (IndexStmt *) index;
}
if (constraint->name != NULL)
index->idxname = pstrdup(constraint->name);
else if (constraint->contype == CONSTR_PRIMARY)
index->idxname = makeObjectName(stmt->relname, NULL, "pkey");
else
index->idxname = NULL;
index->relname = stmt->relname;
index->accessMethod = "btree";
index->indexParams = NIL;
index->withClause = NIL;
index->whereClause = NULL;
keys = constraint->keys;
while (keys != NIL)
{
key = lfirst(keys);
columns = stmt->tableElts;
column = NULL;
while (columns != NIL)
{
column = lfirst(columns);
if (strcasecmp(column->colname, key->name) == 0)
break;
else
column = NULL;
columns = lnext(columns);
}
if (column == NULL)
elog(ERROR, "CREATE TABLE column '%s' in key does not exist", key->name);
if (constraint->contype == CONSTR_PRIMARY)
column->is_not_null = TRUE;
iparam = makeNode(IndexElem);
iparam->name = pstrdup(column->colname);
iparam->args = NIL;
iparam->class = NULL;
iparam->typename = NULL;
index->indexParams = lappend(index->indexParams, iparam);
if (index->idxname == NULL)
index->idxname = CreateIndexName(stmt->relname, iparam->name, "key", ilist);
keys = lnext(keys);
}
if (index->idxname == NULL) /* should not happen */
elog(ERROR, "CREATE TABLE: failed to make implicit index name");
ilist = lappend(ilist, index);
dlist = lnext(dlist);
}
/* OK, now finally, if there is a primary key, then make sure that there aren't any redundant
* unique indices defined on columns. This can arise if someone specifies UNIQUE explicitly
* or if a SERIAL column was defined along with a table PRIMARY KEY constraint.
* - thomas 1999-05-11
*/
if (pkey != NULL)
{
dlist = ilist;
ilist = NIL;
while (dlist != NIL)
{
List *pcols, *icols;
int plen, ilen;
int keep = TRUE;
index = lfirst(dlist);
pcols = pkey->indexParams;
icols = index->indexParams;
plen = length(pcols);
ilen = length(icols);
/* Not the same as the primary key? Then we should look... */
if ((index != pkey) && (ilen == plen))
{
keep = FALSE;
while ((pcols != NIL) && (icols != NIL))
{
IndexElem *pcol = lfirst(pcols);
IndexElem *icol = lfirst(icols);
char *pname = pcol->name;
char *iname = icol->name;
/* different names? then no match... */
if (strcmp(iname, pname) != 0)
{
keep = TRUE;
break;
}
pcols = lnext(pcols);
icols = lnext(icols);
}
}
if (keep)
ilist = lappend(ilist, index);
dlist = lnext(dlist);
}
}
dlist = ilist;
while (dlist != NIL)
{
index = lfirst(dlist);
elog(NOTICE, "CREATE TABLE/%s will create implicit index '%s' for table '%s'",
(index->primary ? "PRIMARY KEY" : "UNIQUE"),
index->idxname, stmt->relname);
dlist = lnext(dlist);
}
q->utilityStmt = (Node *) stmt;
extras_before = blist;
extras_after = ilist;
return q;
} /* transformCreateStmt() */
/*
* transformIndexStmt -
* transforms the qualification of the index statement
*/
static Query *
transformIndexStmt(ParseState *pstate, IndexStmt *stmt)
{
Query *qry;
qry = makeNode(Query);
qry->commandType = CMD_UTILITY;
/* take care of the where clause */
stmt->whereClause = transformWhereClause(pstate, stmt->whereClause, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
stmt->rangetable = pstate->p_rtable;
qry->utilityStmt = (Node *) stmt;
return qry;
}
/*
* transformExtendStmt -
* transform the qualifications of the Extend Index Statement
*
*/
static Query *
transformExtendStmt(ParseState *pstate, ExtendStmt *stmt)
{
Query *qry;
qry = makeNode(Query);
qry->commandType = CMD_UTILITY;
/* take care of the where clause */
stmt->whereClause = transformWhereClause(pstate, stmt->whereClause, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
stmt->rangetable = pstate->p_rtable;
qry->utilityStmt = (Node *) stmt;
return qry;
}
/*
* transformRuleStmt -
* transform a Create Rule Statement. The actions is a list of parse
* trees which is transformed into a list of query trees.
*/
static Query *
transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
{
Query *qry;
Query *action;
List *actions;
qry = makeNode(Query);
qry->commandType = CMD_UTILITY;
/*
* 'instead nothing' rules with a qualification need a query a
* rangetable so the rewrite handler can add the negated rule
* qualification to the original query. We create a query with the new
* command type CMD_NOTHING here that is treated special by the
* rewrite system.
*/
if (stmt->actions == NIL)
{
Query *nothing_qry = makeNode(Query);
nothing_qry->commandType = CMD_NOTHING;
addRangeTableEntry(pstate, stmt->object->relname, "*CURRENT*",
FALSE, FALSE, FALSE);
addRangeTableEntry(pstate, stmt->object->relname, "*NEW*",
FALSE, FALSE, FALSE);
nothing_qry->rtable = pstate->p_rtable;
stmt->actions = lappend(NIL, nothing_qry);
}
actions = stmt->actions;
/*
* transform each statment, like parse_analyze()
*/
while (actions != NIL)
{
/*
* NOTE: 'CURRENT' must always have a varno equal to 1 and 'NEW'
* equal to 2.
*/
addRangeTableEntry(pstate, stmt->object->relname, "*CURRENT*",
FALSE, FALSE, FALSE);
addRangeTableEntry(pstate, stmt->object->relname, "*NEW*",
FALSE, FALSE, FALSE);
pstate->p_last_resno = 1;
pstate->p_is_rule = true; /* for expand all */
pstate->p_hasAggs = false;
action = (Query *) lfirst(actions);
if (action->commandType != CMD_NOTHING)
lfirst(actions) = transformStmt(pstate, lfirst(actions));
actions = lnext(actions);
}
/* take care of the where clause */
stmt->whereClause = transformWhereClause(pstate, stmt->whereClause, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->utilityStmt = (Node *) stmt;
return qry;
}
/*
* transformSelectStmt -
* transforms a Select Statement
*
*/
static Query *
transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
{
Query *qry = makeNode(Query);
Node *fromQual;
qry->commandType = CMD_SELECT;
/* set up a range table */
makeRangeTable(pstate, stmt->fromClause, &fromQual);
qry->uniqueFlag = stmt->unique;
qry->into = stmt->into;
qry->isTemp = stmt->istemp;
qry->isPortal = FALSE;
qry->targetList = transformTargetList(pstate, stmt->targetList);
qry->qual = transformWhereClause(pstate, stmt->whereClause, fromQual);
/* Initial processing of HAVING clause is just like WHERE clause.
* Additional work will be done in optimizer/plan/planner.c.
*/
qry->havingQual = transformWhereClause(pstate, stmt->havingClause, NULL);
qry->groupClause = transformGroupClause(pstate,
stmt->groupClause,
qry->targetList);
qry->sortClause = transformSortClause(pstate,
stmt->sortClause,
qry->targetList,
qry->uniqueFlag);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
parseCheckAggregates(pstate, qry);
/*
* The INSERT INTO ... SELECT ... could have a UNION in child, so
* unionClause may be false
*/
qry->unionall = stmt->unionall;
/*
* Just hand through the unionClause and intersectClause. We will
* handle it in the function Except_Intersect_Rewrite()
*/
qry->unionClause = stmt->unionClause;
qry->intersectClause = stmt->intersectClause;
qry->rtable = pstate->p_rtable;
if (stmt->forUpdate != NULL)
transformForUpdate(qry, stmt->forUpdate);
return (Query *) qry;
}
/*
* transformUpdateStmt -
* transforms an update statement
*
*/
static Query *
transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
{
Query *qry = makeNode(Query);
List *origTargetList;
List *tl;
qry->commandType = CMD_UPDATE;
pstate->p_is_update = true;
/*
* the FROM clause is non-standard SQL syntax. We used to be able to
* do this with REPLACE in POSTQUEL so we keep the feature.
*/
makeRangeTable(pstate, stmt->fromClause, NULL);
setTargetTable(pstate, stmt->relname);
qry->targetList = transformTargetList(pstate, stmt->targetList);
qry->qual = transformWhereClause(pstate, stmt->whereClause, NULL);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->rtable = pstate->p_rtable;
qry->resultRelation = refnameRangeTablePosn(pstate, stmt->relname, NULL);
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs)
parseCheckAggregates(pstate, qry);
/*
* Now we are done with SELECT-like processing, and can get on with
* transforming the target list to match the UPDATE target columns.
*/
/* Prepare to assign non-conflicting resnos to resjunk attributes */
if (pstate->p_last_resno <= pstate->p_target_relation->rd_rel->relnatts)
pstate->p_last_resno = pstate->p_target_relation->rd_rel->relnatts + 1;
/* Prepare non-junk columns for assignment to target table */
origTargetList = stmt->targetList;
foreach(tl, qry->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
Resdom *resnode = tle->resdom;
ResTarget *origTarget;
if (resnode->resjunk)
{
/* Resjunk nodes need no additional processing, but be sure they
* have names and resnos that do not match any target columns;
* else rewriter or planner might get confused.
*/
resnode->resname = "?resjunk?";
resnode->resno = (AttrNumber) pstate->p_last_resno++;
continue;
}
if (origTargetList == NIL)
elog(ERROR, "UPDATE target count mismatch --- internal error");
origTarget = (ResTarget *) lfirst(origTargetList);
updateTargetListEntry(pstate, tle, origTarget->name,
attnameAttNum(pstate->p_target_relation,
origTarget->name),
origTarget->indirection);
origTargetList = lnext(origTargetList);
}
if (origTargetList != NIL)
elog(ERROR, "UPDATE target count mismatch --- internal error");
return (Query *) qry;
}
/*
* transformCursorStmt -
* transform a Create Cursor Statement
*
*/
static Query *
transformCursorStmt(ParseState *pstate, SelectStmt *stmt)
{
Query *qry;
qry = transformSelectStmt(pstate, stmt);
qry->into = stmt->portalname;
qry->isTemp = stmt->istemp;
qry->isPortal = TRUE;
qry->isBinary = stmt->binary; /* internal portal */
return qry;
}
/* This function steps through the tree
* built up by the select_w_o_sort rule
* and builds a list of all SelectStmt Nodes found
* The built up list is handed back in **select_list.
* If one of the SelectStmt Nodes has the 'unionall' flag
* set to true *unionall_present hands back 'true' */
void
create_select_list(Node *ptr, List **select_list, bool *unionall_present)
{
if (IsA(ptr, SelectStmt))
{
*select_list = lappend(*select_list, ptr);
if (((SelectStmt *) ptr)->unionall == TRUE)
*unionall_present = TRUE;
return;
}
/* Recursively call for all arguments. A NOT expr has no lexpr! */
if (((A_Expr *) ptr)->lexpr != NULL)
create_select_list(((A_Expr *) ptr)->lexpr, select_list, unionall_present);
create_select_list(((A_Expr *) ptr)->rexpr, select_list, unionall_present);
}
/* Changes the A_Expr Nodes to Expr Nodes and exchanges ANDs and ORs.
* The reason for the exchange is easy: We implement INTERSECTs and EXCEPTs
* by rewriting these queries to semantically equivalent queries that use
* IN and NOT IN subselects. To be able to use all three operations
* (UNIONs INTERSECTs and EXCEPTs) in one complex query we have to
* translate the queries into Disjunctive Normal Form (DNF). Unfortunately
* there is no function 'dnfify' but there is a function 'cnfify'
* which produces DNF when we exchange ANDs and ORs before calling
* 'cnfify' and exchange them back in the result.
*
* If an EXCEPT or INTERSECT is present *intersect_present
* hands back 'true' */
Node *
A_Expr_to_Expr(Node *ptr, bool *intersect_present)
{
Node *result = NULL;
switch (nodeTag(ptr))
{
case T_A_Expr:
{
A_Expr *a = (A_Expr *) ptr;
switch (a->oper)
{
case AND:
{
Expr *expr = makeNode(Expr);
Node *lexpr = A_Expr_to_Expr(((A_Expr *) ptr)->lexpr, intersect_present);
Node *rexpr = A_Expr_to_Expr(((A_Expr *) ptr)->rexpr, intersect_present);
*intersect_present = TRUE;
expr->typeOid = BOOLOID;
expr->opType = OR_EXPR;
expr->args = makeList(lexpr, rexpr, -1);
result = (Node *) expr;
break;
}
case OR:
{
Expr *expr = makeNode(Expr);
Node *lexpr = A_Expr_to_Expr(((A_Expr *) ptr)->lexpr, intersect_present);
Node *rexpr = A_Expr_to_Expr(((A_Expr *) ptr)->rexpr, intersect_present);
expr->typeOid = BOOLOID;
expr->opType = AND_EXPR;
expr->args = makeList(lexpr, rexpr, -1);
result = (Node *) expr;
break;
}
case NOT:
{
Expr *expr = makeNode(Expr);
Node *rexpr = A_Expr_to_Expr(((A_Expr *) ptr)->rexpr, intersect_present);
expr->typeOid = BOOLOID;
expr->opType = NOT_EXPR;
expr->args = makeList(rexpr, -1);
result = (Node *) expr;
break;
}
}
break;
}
default:
result = ptr;
}
return result;
}
void
CheckSelectForUpdate(Query *qry)
{
if (qry->unionClause != NULL)
elog(ERROR, "SELECT FOR UPDATE is not allowed with UNION/INTERSECT/EXCEPT clause");
if (qry->uniqueFlag != NULL)
elog(ERROR, "SELECT FOR UPDATE is not allowed with DISTINCT clause");
if (qry->groupClause != NULL)
elog(ERROR, "SELECT FOR UPDATE is not allowed with GROUP BY clause");
if (qry->hasAggs)
elog(ERROR, "SELECT FOR UPDATE is not allowed with AGGREGATE");
}
static void
transformForUpdate(Query *qry, List *forUpdate)
{
List *rowMark = NULL;
RowMark *newrm;
List *l;
Index i;
CheckSelectForUpdate(qry);
if (lfirst(forUpdate) == NULL) /* all tables */
{
i = 1;
foreach(l, qry->rtable)
{
newrm = makeNode(RowMark);
newrm->rti = i++;
newrm->info = ROW_MARK_FOR_UPDATE | ROW_ACL_FOR_UPDATE;
rowMark = lappend(rowMark, newrm);
}
qry->rowMark = nconc(qry->rowMark, rowMark);
return;
}
foreach(l, forUpdate)
{
List *l2;
List *l3;
i = 1;
foreach(l2, qry->rtable)
{
if (strcmp(((RangeTblEntry *) lfirst(l2))->refname, lfirst(l)) == 0)
{
foreach(l3, rowMark)
{
if (((RowMark *) lfirst(l3))->rti == i) /* duplicate */
break;
}
if (l3 == NULL)
{
newrm = makeNode(RowMark);
newrm->rti = i;
newrm->info = ROW_MARK_FOR_UPDATE | ROW_ACL_FOR_UPDATE;
rowMark = lappend(rowMark, newrm);
}
break;
}
i++;
}
if (l2 == NULL)
elog(ERROR, "FOR UPDATE: relation %s not found in FROM clause", lfirst(l));
}
qry->rowMark = rowMark;
return;
}
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