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postgres/src/backend/parser/analyze.c
Tom Lane 7f76eab140 Rewrite parser's handling of INSERT ... SELECT so that processing 
of the SELECT part of the statement is just like a plain SELECT.  All
INSERT-specific processing happens after the SELECT parsing is done.
This eliminates many problems, e.g. INSERT ... SELECT ... GROUP BY using
the wrong column labels.  Ensure that DEFAULT clauses are coerced to
the target column type, whether or not stored clause produces the right
type.  Substantial cleanup of parser's array support.
1999-07-19 00:26:20 +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 1.116 1999/07/19 00:26:18 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);
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);
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);
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->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);
return (Query *) qry;
}
/*
* transformInsertStmt -
* transform an Insert Statement
*/
static Query *
transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
{
Query *qry = makeNode(Query);
Node *fromQual;
List *icolumns;
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,
NIL,
qry->targetList,
qry->uniqueFlag);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs || qry->groupClause)
parseCheckAggregates(pstate, qry);
/*
* If there is a havingQual but there are no aggregates, then there is
* something wrong with the query because HAVING must contain
* aggregates in its expressions! Otherwise the query could have been
* formulated using the WHERE clause.
*/
if (qry->havingQual && ! qry->hasAggs)
elog(ERROR, "SELECT/HAVING requires aggregates to be valid");
/*
* 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 = makeTargetNames(pstate, stmt->cols);
/* Prepare non-junk columns for assignment to target table */
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)
elog(ERROR, "INSERT has more expressions than target columns");
id = (Ident *) lfirst(icolumns);
updateTargetListEntry(pstate, tle, id->name, id->indirection);
icolumns = lnext(icolumns);
}
/*
* 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)
{
Form_pg_attribute thisatt = att[defval[ndef].adnum - 1];
TargetEntry *te;
foreach(tl, qry->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
Resdom *resnode = tle->resdom;
if (resnode->resjunk)
continue; /* ignore resjunk nodes */
if (namestrcmp(&(thisatt->attname), resnode->resname) == 0)
break;
}
if (tl != NIL) /* something given for this attr */
continue;
/*
* No user-supplied value, so add a targetentry with DEFAULT expr
* and correct data for the target column.
*/
te = makeTargetEntry(
makeResdom(defval[ndef].adnum,
thisatt->atttypid,
thisatt->atttypmod,
pstrdup(nameout(&(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, NIL);
}
}
if (stmt->forUpdate != NULL)
transformForUpdate(qry, stmt->forUpdate);
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;
elements = stmt->tableElts;
constraints = stmt->constraints;
columns = NIL;
dlist = NIL;
while (elements != NIL)
{
element = lfirst(elements);
switch (nodeTag(element))
{
case T_ColumnDef:
column = (ColumnDef *) element;
columns = lappend(columns, column);
if (column->is_sequence)
{
char *sname;
char *cstring;
CreateSeqStmt *sequence;
sname = makeObjectName(stmt->relname, column->colname,
"seq");
constraint = makeNode(Constraint);
constraint->contype = CONSTR_DEFAULT;
constraint->name = sname;
cstring = palloc(10 + strlen(constraint->name) + 3 + 1);
strcpy(cstring, "nextval('\"");
strcat(cstring, constraint->name);
strcat(cstring, "\"')");
constraint->def = cstring;
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);
}
if (column->constraints != NIL)
{
clist = column->constraints;
while (clist != NIL)
{
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->defval != NULL)
elog(ERROR, "CREATE TABLE/DEFAULT multiple values specified"
" for '%s.%s'", stmt->relname, column->colname);
column->defval = constraint->def;
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:
constraints = lappend(constraints, constraint);
if (constraint->name == NULL)
constraint->name = makeObjectName(stmt->relname, column->colname, NULL);
break;
default:
elog(ERROR, "parser: unrecognized constraint (internal error)", NULL);
break;
}
clist = lnext(clist);
}
}
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)", NULL);
break;
default:
elog(ERROR, "parser: unrecognized constraint (internal error)", NULL);
break;
}
break;
default:
elog(ERROR, "parser: unrecognized node (internal error)", NULL);
}
elements = lnext(elements);
}
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) && (length(lfirst(pkey->indexParams)) == 1))
{
dlist = ilist;
ilist = NIL;
while (dlist != NIL)
{
int keep = TRUE;
index = lfirst(dlist);
/*
* has a single column argument, so might be a conflicting
* index...
*/
if ((index != pkey)
&& (length(index->indexParams) == 1))
{
char *pname = ((IndexElem *) lfirst(index->indexParams))->name;
char *iname = ((IndexElem *) lfirst(index->indexParams))->name;
/* same names? then don't keep... */
keep = (strcmp(iname, pname) != 0);
}
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);
addRangeTableEntry(pstate, stmt->object->relname, "*NEW*",
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);
addRangeTableEntry(pstate, stmt->object->relname, "*NEW*",
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,
NIL,
qry->targetList,
qry->uniqueFlag);
qry->hasSubLinks = pstate->p_hasSubLinks;
qry->hasAggs = pstate->p_hasAggs;
if (pstate->p_hasAggs || qry->groupClause)
parseCheckAggregates(pstate, qry);
/*
* If there is a havingQual but there are no aggregates, then there is
* something wrong with the query because HAVING must contain
* aggregates in its expressions! Otherwise the query could have been
* formulated using the WHERE clause.
*/
if (qry->havingQual && ! qry->hasAggs)
elog(ERROR, "SELECT/HAVING requires aggregates to be valid");
/*
* 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, 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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