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c65ea0e040
varchar length. Cleans up code so attlen is always length. Removed varchar() hack added earlier. Will fix bug in selecting varchar() fields, and varchar() can be variable length.
345 lines
8.0 KiB
C
345 lines
8.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* preptlist.c--
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* Routines to preprocess the parse tree target list
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.7 1998/01/16 23:20:09 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include <string.h>
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#include "postgres.h"
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#include "catalog/pg_type.h"
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#include "nodes/pg_list.h"
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#include "nodes/relation.h"
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#include "nodes/primnodes.h"
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#include "nodes/parsenodes.h"
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#include "nodes/makefuncs.h"
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#include "utils/builtins.h"
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#include "utils/lsyscache.h"
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#include "utils/palloc.h"
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#include "parser/parse_type.h"
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#include "parser/parsetree.h" /* for getrelid() */
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#include "optimizer/internal.h"
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#include "optimizer/prep.h"
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#include "optimizer/clauses.h"
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#include "optimizer/tlist.h"
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static List *
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expand_targetlist(List *tlist, Oid relid, int command_type,
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Index result_relation);
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static List *
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replace_matching_resname(List *new_tlist,
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List *old_tlist);
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static List *
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new_relation_targetlist(Oid relid, Index rt_index,
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NodeTag node_type);
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/*
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* preprocess-targetlist--
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* Driver for preprocessing the parse tree targetlist.
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*
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* 1. Deal with appends and replaces by filling missing attributes
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* in the target list.
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* 2. Reset operator OIDs to the appropriate regproc ids.
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*
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* Returns the new targetlist.
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*/
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List *
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preprocess_targetlist(List *tlist,
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int command_type,
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Index result_relation,
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List *range_table)
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{
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List *expanded_tlist = NIL;
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Oid relid = InvalidOid;
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List *t_list = NIL;
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List *temp = NIL;
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if (result_relation >= 1 && command_type != CMD_SELECT)
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{
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relid = getrelid(result_relation, range_table);
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}
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/*
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* for heap_formtuple to work, the targetlist must match the exact
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* order of the attributes. We also need to fill in the missing
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* attributes here. -ay 10/94
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*/
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expanded_tlist =
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expand_targetlist(tlist, relid, command_type, result_relation);
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/* XXX should the fix-opids be this early?? */
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/* was mapCAR */
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foreach(temp, expanded_tlist)
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{
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TargetEntry *tle = lfirst(temp);
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if (tle->expr)
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fix_opid(tle->expr);
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}
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t_list = copyObject(expanded_tlist);
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/* ------------------
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* for "replace" or "delete" queries, add ctid of the result
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* relation into the target list so that the ctid can get
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* propogate through the execution and in the end ExecReplace()
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* will find the right tuple to replace or delete. This
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* extra field will be removed in ExecReplace().
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* For convinient, we append this extra field to the end of
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* the target list.
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* ------------------
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*/
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if (command_type == CMD_UPDATE || command_type == CMD_DELETE)
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{
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TargetEntry *ctid;
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Resdom *resdom;
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Var *var;
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resdom = makeResdom(length(t_list) + 1,
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27,
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6,
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"ctid",
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0,
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0,
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1);
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var = makeVar(result_relation, -1, 27, result_relation, -1);
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ctid = makeNode(TargetEntry);
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ctid->resdom = resdom;
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ctid->expr = (Node *) var;
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t_list = lappend(t_list, ctid);
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}
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return (t_list);
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}
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/*****************************************************************************
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*
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* TARGETLIST EXPANSION
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*
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*****************************************************************************/
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/*
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* expand-targetlist--
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* Given a target list as generated by the parser and a result relation,
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* add targetlist entries for the attributes which have not been used.
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*
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* XXX This code is only supposed to work with unnested relations.
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*
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* 'tlist' is the original target list
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* 'relid' is the relid of the result relation
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* 'command' is the update command
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*
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* Returns the expanded target list, sorted in resno order.
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*/
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static List *
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expand_targetlist(List *tlist,
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Oid relid,
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int command_type,
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Index result_relation)
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{
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NodeTag node_type = T_Invalid;
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switch (command_type)
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{
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case CMD_INSERT:
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node_type = (NodeTag) T_Const;
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break;
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case CMD_UPDATE:
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node_type = (NodeTag) T_Var;
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break;
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}
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if (node_type != T_Invalid)
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{
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List *ntlist = new_relation_targetlist(relid,
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result_relation,
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node_type);
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return (replace_matching_resname(ntlist, tlist));
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}
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else
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{
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return (tlist);
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}
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}
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static List *
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replace_matching_resname(List *new_tlist, List *old_tlist)
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{
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List *temp,
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*i;
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List *t_list = NIL;
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foreach(i, new_tlist)
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{
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TargetEntry *new_tle = (TargetEntry *) lfirst(i);
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TargetEntry *matching_old_tl = NULL;
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foreach(temp, old_tlist)
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{
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TargetEntry *old_tle = (TargetEntry *) lfirst(temp);
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old_tle = lfirst(temp);
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if (!strcmp(old_tle->resdom->resname,
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new_tle->resdom->resname))
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{
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matching_old_tl = old_tle;
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break;
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}
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}
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if (matching_old_tl)
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{
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matching_old_tl->resdom->resno =
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new_tle->resdom->resno;
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t_list = lappend(t_list, matching_old_tl);
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}
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else
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{
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t_list = lappend(t_list, new_tle);
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}
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}
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/*
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* It is possible that 'old_tlist' has some negative attributes (i.e.
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* negative resnos). This only happens if this is a replace/append
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* command and we explicitly specify a system attribute. Of course
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* this is not a very good idea if this is a user query, but on the
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* other hand the rule manager uses this mechanism to replace rule
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* locks.
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*
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* So, copy all these entries to the end of the target list and set their
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* 'resjunk' value to 1 to show that these are special attributes and
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* have to be treated specially by the executor!
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*/
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foreach(temp, old_tlist)
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{
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TargetEntry *old_tle,
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*new_tl;
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Resdom *newresno;
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old_tle = lfirst(temp);
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if (old_tle->resdom->resno < 0)
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{
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newresno = (Resdom *) copyObject((Node *) old_tle->resdom);
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newresno->resno = length(t_list) + 1;
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newresno->resjunk = 1;
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new_tl = MakeTLE(newresno, old_tle->expr);
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t_list = lappend(t_list, new_tl);
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}
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}
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return (t_list);
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}
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/*
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* new-relation-targetlist--
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* Generate a targetlist for the relation with relation OID 'relid'
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* and rangetable index 'rt-index'.
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*
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* Returns the new targetlist.
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*/
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static List *
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new_relation_targetlist(Oid relid, Index rt_index, NodeTag node_type)
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{
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AttrNumber attno;
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List *t_list = NIL;
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char *attname;
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Oid atttype = 0;
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int16 typlen = 0;
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bool attisset = false;
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/* Oid type_id; */
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/* type_id = RelationIdGetTypeId(relid); */
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for (attno = 1; attno <= get_relnatts(relid); attno++)
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{
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attname = get_attname( /* type_id, */ relid, attno);
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atttype = get_atttype( /* type_id, */ relid, attno);
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/*
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* Since this is an append or replace, the size of any set
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* attribute is the size of the OID used to represent it.
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*/
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attisset = get_attisset( /* type_id, */ relid, attname);
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if (attisset)
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typlen = typeLen(typeidType(OIDOID));
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else
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typlen = get_typlen(atttype);
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switch (node_type)
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{
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case T_Const:
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{
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struct varlena *typedefault = get_typdefault(atttype);
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int temp = 0;
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Const *temp2 = (Const *) NULL;
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TargetEntry *temp3 = (TargetEntry *) NULL;
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if (typedefault == NULL)
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temp = 0;
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else
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temp = typlen;
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temp2 = makeConst(atttype,
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temp,
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(Datum) typedefault,
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(typedefault == (struct varlena *) NULL),
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/* XXX this is bullshit */
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false,
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false, /* not a set */
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false);
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temp3 = MakeTLE(makeResdom(attno,
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atttype,
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typlen,
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attname,
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0,
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(Oid) 0,
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0),
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(Node *) temp2);
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t_list = lappend(t_list, temp3);
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break;
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}
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case T_Var:
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{
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Var *temp_var = (Var *) NULL;
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TargetEntry *temp_list = NULL;
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temp_var =
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makeVar(rt_index, attno, atttype, rt_index, attno);
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temp_list = MakeTLE(makeResdom(attno,
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atttype,
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typlen,
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attname,
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0,
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(Oid) 0,
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0),
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(Node *) temp_var);
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t_list = lappend(t_list, temp_list);
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break;
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}
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default: /* do nothing */
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break;
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}
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}
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return (t_list);
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}
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