diff options
Diffstat (limited to 'src/backend/commands/view.c')
| -rw-r--r-- | src/backend/commands/view.c | 427 |
1 files changed, 215 insertions, 212 deletions
diff --git a/src/backend/commands/view.c b/src/backend/commands/view.c index 3cd011ace25..99439de9ce3 100644 --- a/src/backend/commands/view.c +++ b/src/backend/commands/view.c @@ -1,17 +1,17 @@ /*------------------------------------------------------------------------- * * view.c-- - * use rewrite rules to construct views + * use rewrite rules to construct views * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/commands/view.c,v 1.8 1997/08/22 14:22:14 vadim Exp $ + * $Header: /cvsroot/pgsql/src/backend/commands/view.c,v 1.9 1997/09/07 04:41:06 momjian Exp $ * *------------------------------------------------------------------------- */ -#include <stdio.h> /* for sprintf() */ +#include <stdio.h> /* for sprintf() */ #include <string.h> #include <postgres.h> @@ -42,69 +42,74 @@ *--------------------------------------------------------------------- */ static void -DefineVirtualRelation(char *relname, List *tlist) +DefineVirtualRelation(char *relname, List * tlist) { - CreateStmt createStmt; - List *attrList, *t; - TargetEntry *entry; - Resdom *res; - char *resname; - char *restypename; - - /* - * create a list with one entry per attribute of this relation. - * Each entry is a two element list. The first element is the - * name of the attribute (a string) and the second the name of the type - * (NOTE: a string, not a type id!). - */ - attrList = NIL; - if (tlist!=NIL) { - foreach (t, tlist ) { - ColumnDef *def = makeNode(ColumnDef); - TypeName *typename; - - /* - * find the names of the attribute & its type - */ - entry = lfirst(t); - res = entry->resdom; - resname = res->resname; - restypename = tname(get_id_type(res->restype)); - - typename = makeNode(TypeName); - - typename->name = pstrdup(restypename); - def->colname = pstrdup(resname); - - def->typename = typename; - - def->is_not_null = false; - def->defval = (char*) NULL; - - attrList = lappend(attrList, def); + CreateStmt createStmt; + List *attrList, + *t; + TargetEntry *entry; + Resdom *res; + char *resname; + char *restypename; + + /* + * create a list with one entry per attribute of this relation. Each + * entry is a two element list. The first element is the name of the + * attribute (a string) and the second the name of the type (NOTE: a + * string, not a type id!). + */ + attrList = NIL; + if (tlist != NIL) + { + foreach(t, tlist) + { + ColumnDef *def = makeNode(ColumnDef); + TypeName *typename; + + /* + * find the names of the attribute & its type + */ + entry = lfirst(t); + res = entry->resdom; + resname = res->resname; + restypename = tname(get_id_type(res->restype)); + + typename = makeNode(TypeName); + + typename->name = pstrdup(restypename); + def->colname = pstrdup(resname); + + def->typename = typename; + + def->is_not_null = false; + def->defval = (char *) NULL; + + attrList = lappend(attrList, def); + } } - } else { - elog ( WARN, "attempted to define virtual relation with no attrs"); - } - - /* - * now create the parametesr for keys/inheritance etc. - * All of them are nil... - */ - createStmt.relname = relname; - createStmt.tableElts = attrList; -/* createStmt.tableType = NULL;*/ - createStmt.inhRelnames = NIL; - createStmt.archiveType = ARCH_NONE; - createStmt.location = -1; - createStmt.archiveLoc = -1; - createStmt.constraints = NIL; - - /* - * finally create the relation... - */ - DefineRelation(&createStmt); -} + else + { + elog(WARN, "attempted to define virtual relation with no attrs"); + } + + /* + * now create the parametesr for keys/inheritance etc. All of them are + * nil... + */ + createStmt.relname = relname; + createStmt.tableElts = attrList; +/* createStmt.tableType = NULL;*/ + createStmt.inhRelnames = NIL; + createStmt.archiveType = ARCH_NONE; + createStmt.location = -1; + createStmt.archiveLoc = -1; + createStmt.constraints = NIL; + + /* + * finally create the relation... + */ + DefineRelation(&createStmt); +} /*------------------------------------------------------------------ * makeViewRetrieveRuleName @@ -118,84 +123,87 @@ DefineVirtualRelation(char *relname, List *tlist) * XXX it also means viewName cannot be 16 chars long! - ay 11/94 *------------------------------------------------------------------ */ -char * +char * MakeRetrieveViewRuleName(char *viewName) { /* - char buf[100]; + char buf[100]; - memset(buf, 0, sizeof(buf)); - sprintf(buf, "_RET%.*s", NAMEDATALEN, viewName->data); - buf[15] = '\0'; - namestrcpy(rule_name, buf); + memset(buf, 0, sizeof(buf)); + sprintf(buf, "_RET%.*s", NAMEDATALEN, viewName->data); + buf[15] = '\0'; + namestrcpy(rule_name, buf); */ - char *buf; - buf = palloc(strlen(viewName) + 5); - sprintf(buf, "_RET%s",viewName); - return buf; + char *buf; + + buf = palloc(strlen(viewName) + 5); + sprintf(buf, "_RET%s", viewName); + return buf; } static RuleStmt * -FormViewRetrieveRule(char *viewName, Query *viewParse) +FormViewRetrieveRule(char *viewName, Query * viewParse) { - RuleStmt *rule; - char *rname; - Attr *attr; - - /* - * Create a RuleStmt that corresponds to the suitable - * rewrite rule args for DefineQueryRewrite(); - */ - rule = makeNode(RuleStmt); - rname = MakeRetrieveViewRuleName(viewName); - - attr = makeNode(Attr); - attr->relname = pstrdup(viewName); -/* attr->refname = pstrdup(viewName);*/ - rule->rulename = pstrdup(rname); - rule->whereClause = NULL; - rule->event = CMD_SELECT; - rule->object = attr; - rule->instead = true; - rule->actions = lcons(viewParse, NIL); - - return rule; + RuleStmt *rule; + char *rname; + Attr *attr; + + /* + * Create a RuleStmt that corresponds to the suitable rewrite rule + * args for DefineQueryRewrite(); + */ + rule = makeNode(RuleStmt); + rname = MakeRetrieveViewRuleName(viewName); + + attr = makeNode(Attr); + attr->relname = pstrdup(viewName); +/* attr->refname = pstrdup(viewName);*/ + rule->rulename = pstrdup(rname); + rule->whereClause = NULL; + rule->event = CMD_SELECT; + rule->object = attr; + rule->instead = true; + rule->actions = lcons(viewParse, NIL); + + return rule; } static void -DefineViewRules(char *viewName, Query *viewParse) +DefineViewRules(char *viewName, Query * viewParse) { - RuleStmt *retrieve_rule = NULL; + RuleStmt *retrieve_rule = NULL; + #ifdef NOTYET - RuleStmt *replace_rule = NULL; - RuleStmt *append_rule = NULL; - RuleStmt *delete_rule = NULL; + RuleStmt *replace_rule = NULL; + RuleStmt *append_rule = NULL; + RuleStmt *delete_rule = NULL; + #endif - - retrieve_rule = - FormViewRetrieveRule(viewName, viewParse); - + + retrieve_rule = + FormViewRetrieveRule(viewName, viewParse); + #ifdef NOTYET - - replace_rule = - FormViewReplaceRule(viewName, viewParse); - append_rule = - FormViewAppendRule(viewName, viewParse); - delete_rule = - FormViewDeleteRule(viewName, viewParse); - + + replace_rule = + FormViewReplaceRule(viewName, viewParse); + append_rule = + FormViewAppendRule(viewName, viewParse); + delete_rule = + FormViewDeleteRule(viewName, viewParse); + #endif - - DefineQueryRewrite(retrieve_rule); + + DefineQueryRewrite(retrieve_rule); #ifdef NOTYET - DefineQueryRewrite(replace_rule); - DefineQueryRewrite(append_rule); - DefineQueryRewrite(delete_rule); + DefineQueryRewrite(replace_rule); + DefineQueryRewrite(append_rule); + DefineQueryRewrite(delete_rule); #endif - -} + +} /*--------------------------------------------------------------- * UpdateRangeTableOfViewParse @@ -216,88 +224,84 @@ DefineViewRules(char *viewName, Query *viewParse) *--------------------------------------------------------------- */ static void -UpdateRangeTableOfViewParse(char *viewName, Query *viewParse) +UpdateRangeTableOfViewParse(char *viewName, Query * viewParse) { - List *old_rt; - List *new_rt; - RangeTblEntry *rt_entry1, *rt_entry2; - - /* - * first offset all var nodes by 2 - */ - OffsetVarNodes((Node*)viewParse->targetList, 2); - OffsetVarNodes(viewParse->qual, 2); - - /* - * find the old range table... - */ - old_rt = viewParse->rtable; - - /* - * create the 2 new range table entries and form the new - * range table... - * CURRENT first, then NEW.... - */ - rt_entry1 = - addRangeTableEntry(NULL, (char*)viewName, "*CURRENT*", - FALSE, FALSE, NULL); - rt_entry2 = - addRangeTableEntry(NULL, (char*)viewName, "*NEW*", - FALSE, FALSE, NULL); - new_rt = lcons(rt_entry2, old_rt); - new_rt = lcons(rt_entry1, new_rt); - - /* - * Now the tricky part.... - * Update the range table in place... Be careful here, or - * hell breaks loooooooooooooOOOOOOOOOOOOOOOOOOSE! - */ - viewParse->rtable = new_rt; + List *old_rt; + List *new_rt; + RangeTblEntry *rt_entry1, + *rt_entry2; + + /* + * first offset all var nodes by 2 + */ + OffsetVarNodes((Node *) viewParse->targetList, 2); + OffsetVarNodes(viewParse->qual, 2); + + /* + * find the old range table... + */ + old_rt = viewParse->rtable; + + /* + * create the 2 new range table entries and form the new range + * table... CURRENT first, then NEW.... + */ + rt_entry1 = + addRangeTableEntry(NULL, (char *) viewName, "*CURRENT*", + FALSE, FALSE, NULL); + rt_entry2 = + addRangeTableEntry(NULL, (char *) viewName, "*NEW*", + FALSE, FALSE, NULL); + new_rt = lcons(rt_entry2, old_rt); + new_rt = lcons(rt_entry1, new_rt); + + /* + * Now the tricky part.... Update the range table in place... Be + * careful here, or hell breaks loooooooooooooOOOOOOOOOOOOOOOOOOSE! + */ + viewParse->rtable = new_rt; } /*------------------------------------------------------------------- * 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 + * - 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(char *viewName, Query *viewParse) +DefineView(char *viewName, Query * viewParse) { - List *viewTlist; - - viewTlist = viewParse->targetList; - - /* - * Create the "view" relation - * NOTE: if it already exists, the xaxt will be aborted. - */ - DefineVirtualRelation(viewName, viewTlist); - - /* - * 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 "CURRENT" and "NEW" relations. - * So... add them! - * NOTE: we make the update in place! After this call 'viewParse' - * will never be what it used to be... - */ - UpdateRangeTableOfViewParse(viewName, viewParse); - DefineViewRules(viewName, viewParse); + List *viewTlist; + + viewTlist = viewParse->targetList; + + /* + * Create the "view" relation NOTE: if it already exists, the xaxt + * will be aborted. + */ + DefineVirtualRelation(viewName, viewTlist); + + /* + * 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 + * "CURRENT" and "NEW" relations. So... add them! NOTE: we make the + * update in place! After this call 'viewParse' will never be what it + * used to be... + */ + UpdateRangeTableOfViewParse(viewName, viewParse); + DefineViewRules(viewName, viewParse); } /*------------------------------------------------------------------ @@ -309,23 +313,22 @@ DefineView(char *viewName, Query *viewParse) void RemoveView(char *viewName) { - char* rname; - - /* - * first remove all the "view" rules... - * Currently we only have one! - */ - rname = MakeRetrieveViewRuleName(viewName); - RemoveRewriteRule(rname); - - /* - * we don't really need that, but just in case... - */ - CommandCounterIncrement(); - - /* - * now remove the relation. - */ - heap_destroy(viewName); - pfree(rname); + char *rname; + + /* + * first remove all the "view" rules... Currently we only have one! + */ + rname = MakeRetrieveViewRuleName(viewName); + RemoveRewriteRule(rname); + + /* + * we don't really need that, but just in case... + */ + CommandCounterIncrement(); + + /* + * now remove the relation. + */ + heap_destroy(viewName); + pfree(rname); } |