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Diffstat (limited to 'src/backend/commands/view.c')
| -rw-r--r-- | src/backend/commands/view.c | 268 |
1 files changed, 0 insertions, 268 deletions
diff --git a/src/backend/commands/view.c b/src/backend/commands/view.c deleted file mode 100644 index e21b72a87a5..00000000000 --- a/src/backend/commands/view.c +++ /dev/null @@ -1,268 +0,0 @@ -/*------------------------------------------------------------------------- - * - * view.c - * use rewrite rules to construct views - * - * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group - * Portions Copyright (c) 1994, Regents of the University of California - * - * $Id: view.c,v 1.64 2002/06/20 20:29:27 momjian Exp $ - * - *------------------------------------------------------------------------- - */ -#include "postgres.h" - -#include "access/xact.h" -#include "catalog/heap.h" -#include "catalog/namespace.h" -#include "commands/tablecmds.h" -#include "commands/view.h" -#include "miscadmin.h" -#include "nodes/makefuncs.h" -#include "parser/parse_relation.h" -#include "parser/parse_type.h" -#include "rewrite/rewriteDefine.h" -#include "rewrite/rewriteManip.h" -#include "rewrite/rewriteRemove.h" -#include "rewrite/rewriteSupport.h" -#include "utils/syscache.h" - - -/*--------------------------------------------------------------------- - * DefineVirtualRelation - * - * Create the "view" relation. - * `DefineRelation' does all the work, we just provide the correct - * arguments! - * - * If the relation already exists, then 'DefineRelation' will abort - * the xact... - *--------------------------------------------------------------------- - */ -static Oid -DefineVirtualRelation(const RangeVar *relation, List *tlist) -{ - CreateStmt *createStmt = makeNode(CreateStmt); - List *attrList, - *t; - - /* - * create a list of ColumnDef nodes based on the names and types of - * the (non-junk) targetlist items from the view's SELECT list. - */ - attrList = NIL; - foreach(t, tlist) - { - TargetEntry *entry = lfirst(t); - Resdom *res = entry->resdom; - - if (!res->resjunk) - { - ColumnDef *def = makeNode(ColumnDef); - TypeName *typename = makeNode(TypeName); - - def->colname = pstrdup(res->resname); - - typename->typeid = res->restype; - typename->typmod = res->restypmod; - def->typename = typename; - - def->is_not_null = false; - def->raw_default = NULL; - def->cooked_default = NULL; - def->constraints = NIL; - - attrList = lappend(attrList, def); - } - } - - if (attrList == NIL) - elog(ERROR, "attempted to define virtual relation with no attrs"); - - /* - * now create the parameters for keys/inheritance etc. All of them are - * nil... - */ - createStmt->relation = (RangeVar *) relation; - createStmt->tableElts = attrList; - createStmt->inhRelations = NIL; - createStmt->constraints = NIL; - createStmt->hasoids = false; - - /* - * finally create the relation... - */ - return DefineRelation(createStmt, RELKIND_VIEW); -} - -static RuleStmt * -FormViewRetrieveRule(const RangeVar *view, Query *viewParse) -{ - RuleStmt *rule; - - /* - * Create a RuleStmt that corresponds to the suitable rewrite rule - * args for DefineQueryRewrite(); - */ - rule = makeNode(RuleStmt); - rule->relation = copyObject((RangeVar *) view); - rule->rulename = pstrdup(ViewSelectRuleName); - rule->whereClause = NULL; - rule->event = CMD_SELECT; - rule->instead = true; - rule->actions = makeList1(viewParse); - - return rule; -} - -static void -DefineViewRules(const RangeVar *view, Query *viewParse) -{ - RuleStmt *retrieve_rule; - -#ifdef NOTYET - RuleStmt *replace_rule; - RuleStmt *append_rule; - RuleStmt *delete_rule; -#endif - - retrieve_rule = FormViewRetrieveRule(view, viewParse); - -#ifdef NOTYET - - replace_rule = FormViewReplaceRule(view, viewParse); - append_rule = FormViewAppendRule(view, viewParse); - delete_rule = FormViewDeleteRule(view, viewParse); -#endif - - DefineQueryRewrite(retrieve_rule); - -#ifdef NOTYET - DefineQueryRewrite(replace_rule); - DefineQueryRewrite(append_rule); - DefineQueryRewrite(delete_rule); -#endif - -} - -/*--------------------------------------------------------------- - * UpdateRangeTableOfViewParse - * - * Update the range table of the given parsetree. - * This update consists of adding two new entries IN THE BEGINNING - * of the range table (otherwise the rule system will die a slow, - * horrible and painful death, and we do not want that now, do we?) - * one for the OLD relation and one for the NEW one (both of - * them refer in fact to the "view" relation). - * - * Of course we must also increase the 'varnos' of all the Var nodes - * by 2... - * - * These extra RT entries are not actually used in the query, - * except for run-time permission checking. - *--------------------------------------------------------------- - */ -static Query * -UpdateRangeTableOfViewParse(Oid viewOid, Query *viewParse) -{ - List *new_rt; - RangeTblEntry *rt_entry1, - *rt_entry2; - - /* - * Make a copy of the given parsetree. It's not so much that we don't - * want to scribble on our input, it's that the parser has a bad habit - * of outputting multiple links to the same subtree for constructs - * like BETWEEN, and we mustn't have OffsetVarNodes increment the - * varno of a Var node twice. copyObject will expand any - * multiply-referenced subtree into multiple copies. - */ - viewParse = (Query *) copyObject(viewParse); - - /* - * Create the 2 new range table entries and form the new range - * table... OLD first, then NEW.... - */ - rt_entry1 = addRangeTableEntryForRelation(NULL, viewOid, - makeAlias("*OLD*", NIL), - false, false); - rt_entry2 = addRangeTableEntryForRelation(NULL, viewOid, - makeAlias("*NEW*", NIL), - false, false); - /* Must override addRangeTableEntry's default access-check flags */ - rt_entry1->checkForRead = false; - rt_entry2->checkForRead = false; - - new_rt = lcons(rt_entry1, lcons(rt_entry2, viewParse->rtable)); - - viewParse->rtable = new_rt; - - /* - * Now offset all var nodes by 2, and jointree RT indexes too. - */ - OffsetVarNodes((Node *) viewParse, 2, 0); - - return viewParse; -} - -/*------------------------------------------------------------------- - * DefineView - * - * - takes a "viewname", "parsetree" pair and then - * 1) construct the "virtual" relation - * 2) commit the command but NOT the transaction, - * so that the relation exists - * before the rules are defined. - * 2) define the "n" rules specified in the PRS2 paper - * over the "virtual" relation - *------------------------------------------------------------------- - */ -void -DefineView(const RangeVar *view, Query *viewParse) -{ - Oid viewOid; - - /* - * Create the view relation - * - * NOTE: if it already exists, the xact will be aborted. - */ - viewOid = DefineVirtualRelation(view, viewParse->targetList); - - /* - * The relation we have just created is not visible to any other - * commands running with the same transaction & command id. So, - * increment the command id counter (but do NOT pfree any memory!!!!) - */ - CommandCounterIncrement(); - - /* - * The range table of 'viewParse' does not contain entries for the - * "OLD" and "NEW" relations. So... add them! - */ - viewParse = UpdateRangeTableOfViewParse(viewOid, viewParse); - - /* - * Now create the rules associated with the view. - */ - DefineViewRules(view, viewParse); -} - -/*------------------------------------------------------------------ - * RemoveView - * - * Remove a view given its name - *------------------------------------------------------------------ - */ -void -RemoveView(const RangeVar *view) -{ - Oid viewOid; - - viewOid = RangeVarGetRelid(view, false); - /* - * We just have to drop the relation; the associated rules will be - * cleaned up automatically. - */ - heap_drop_with_catalog(viewOid, allowSystemTableMods); -} |