postgresql/src/backend/parser/parse_utilcmd.c

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/*-------------------------------------------------------------------------
*
* parse_utilcmd.c
* Perform parse analysis work for various utility commands
*
* Formerly we did this work during parse_analyze() in analyze.c. However
* that is fairly unsafe in the presence of querytree caching, since any
* database state that we depend on in making the transformations might be
* obsolete by the time the utility command is executed; and utility commands
* have no infrastructure for holding locks or rechecking plan validity.
* Hence these functions are now called at the start of execution of their
* respective utility commands.
*
* NOTE: in general we must avoid scribbling on the passed-in raw parse
* tree, since it might be in a plan cache. The simplest solution is
* a quick copyObject() call before manipulating the query tree.
*
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/backend/parser/parse_utilcmd.c,v 2.1 2007/06/23 22:12:51 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "commands/tablecmds.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "parser/analyze.h"
#include "parser/gramparse.h"
#include "parser/parse_clause.h"
#include "parser/parse_expr.h"
#include "parser/parse_relation.h"
#include "parser/parse_type.h"
#include "parser/parse_utilcmd.h"
#include "rewrite/rewriteManip.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
/* State shared by transformCreateStmt and its subroutines */
typedef struct
{
const char *stmtType; /* "CREATE TABLE" or "ALTER TABLE" */
RangeVar *relation; /* relation to create */
Relation rel; /* opened/locked rel, if ALTER */
List *inhRelations; /* relations to inherit from */
bool isalter; /* true if altering existing table */
bool hasoids; /* does relation have an OID column? */
List *columns; /* ColumnDef items */
List *ckconstraints; /* CHECK constraints */
List *fkconstraints; /* FOREIGN KEY constraints */
List *ixconstraints; /* index-creating constraints */
List *blist; /* "before list" of things to do before
* creating the table */
List *alist; /* "after list" of things to do after creating
* the table */
IndexStmt *pkey; /* PRIMARY KEY index, if any */
} CreateStmtContext;
/* State shared by transformCreateSchemaStmt and its subroutines */
typedef struct
{
const char *stmtType; /* "CREATE SCHEMA" or "ALTER SCHEMA" */
char *schemaname; /* name of schema */
char *authid; /* owner of schema */
List *sequences; /* CREATE SEQUENCE items */
List *tables; /* CREATE TABLE items */
List *views; /* CREATE VIEW items */
List *indexes; /* CREATE INDEX items */
List *triggers; /* CREATE TRIGGER items */
List *grants; /* GRANT items */
} CreateSchemaStmtContext;
static void transformColumnDefinition(ParseState *pstate,
CreateStmtContext *cxt,
ColumnDef *column);
static void transformTableConstraint(ParseState *pstate,
CreateStmtContext *cxt,
Constraint *constraint);
static void transformInhRelation(ParseState *pstate, CreateStmtContext *cxt,
InhRelation *inhrelation);
static void transformIndexConstraints(ParseState *pstate,
CreateStmtContext *cxt);
static void transformFKConstraints(ParseState *pstate,
CreateStmtContext *cxt,
bool skipValidation,
bool isAddConstraint);
static void transformConstraintAttrs(List *constraintList);
static void transformColumnType(ParseState *pstate, ColumnDef *column);
static void setSchemaName(char *context_schema, char **stmt_schema_name);
/*
* transformCreateStmt -
* parse analysis for CREATE TABLE
*
* Returns a List of utility commands to be done in sequence. One of these
* will be the transformed CreateStmt, but there may be additional actions
* to be done before and after the actual DefineRelation() call.
*
* 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
*/
List *
transformCreateStmt(CreateStmt *stmt, const char *queryString)
{
ParseState *pstate;
CreateStmtContext cxt;
List *result;
List *save_alist;
ListCell *elements;
/*
* We must not scribble on the passed-in CreateStmt, so copy it. (This
* is overkill, but easy.)
*/
stmt = (CreateStmt *) copyObject(stmt);
/* Set up pstate */
pstate = make_parsestate(NULL);
pstate->p_sourcetext = queryString;
cxt.stmtType = "CREATE TABLE";
cxt.relation = stmt->relation;
cxt.rel = NULL;
cxt.inhRelations = stmt->inhRelations;
cxt.isalter = false;
cxt.columns = NIL;
cxt.ckconstraints = NIL;
cxt.fkconstraints = NIL;
cxt.ixconstraints = NIL;
cxt.blist = NIL;
cxt.alist = NIL;
cxt.pkey = NULL;
cxt.hasoids = interpretOidsOption(stmt->options);
/*
* Run through each primary element in the table creation clause. Separate
* column defs from constraints, and do preliminary analysis.
*/
foreach(elements, stmt->tableElts)
{
Node *element = lfirst(elements);
switch (nodeTag(element))
{
case T_ColumnDef:
transformColumnDefinition(pstate, &cxt,
(ColumnDef *) element);
break;
case T_Constraint:
transformTableConstraint(pstate, &cxt,
(Constraint *) element);
break;
case T_FkConstraint:
/* No pre-transformation needed */
cxt.fkconstraints = lappend(cxt.fkconstraints, element);
break;
case T_InhRelation:
transformInhRelation(pstate, &cxt,
(InhRelation *) element);
break;
default:
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(element));
break;
}
}
/*
* transformIndexConstraints wants cxt.alist to contain only index
* statements, so transfer anything we already have into save_alist.
*/
save_alist = cxt.alist;
cxt.alist = NIL;
Assert(stmt->constraints == NIL);
/*
* Postprocess constraints that give rise to index definitions.
*/
transformIndexConstraints(pstate, &cxt);
/*
* Postprocess foreign-key constraints.
*/
transformFKConstraints(pstate, &cxt, true, false);
/*
* Output results.
*/
stmt->tableElts = cxt.columns;
stmt->constraints = cxt.ckconstraints;
result = lappend(cxt.blist, stmt);
result = list_concat(result, cxt.alist);
result = list_concat(result, save_alist);
return result;
}
/*
* transformColumnDefinition -
* transform a single ColumnDef within CREATE TABLE
* Also used in ALTER TABLE ADD COLUMN
*/
static void
transformColumnDefinition(ParseState *pstate, CreateStmtContext *cxt,
ColumnDef *column)
{
bool is_serial;
bool saw_nullable;
bool saw_default;
Constraint *constraint;
ListCell *clist;
cxt->columns = lappend(cxt->columns, column);
/* Check for SERIAL pseudo-types */
is_serial = false;
if (list_length(column->typename->names) == 1)
{
char *typname = strVal(linitial(column->typename->names));
if (strcmp(typname, "serial") == 0 ||
strcmp(typname, "serial4") == 0)
{
is_serial = true;
column->typename->names = NIL;
column->typename->typeid = INT4OID;
}
else if (strcmp(typname, "bigserial") == 0 ||
strcmp(typname, "serial8") == 0)
{
is_serial = true;
column->typename->names = NIL;
column->typename->typeid = INT8OID;
}
}
/* Do necessary work on the column type declaration */
transformColumnType(pstate, column);
/* Special actions for SERIAL pseudo-types */
if (is_serial)
{
Oid snamespaceid;
char *snamespace;
char *sname;
char *qstring;
A_Const *snamenode;
FuncCall *funccallnode;
CreateSeqStmt *seqstmt;
AlterSeqStmt *altseqstmt;
List *attnamelist;
/*
* Determine namespace and name to use for the sequence.
*
* Although we use ChooseRelationName, it's not guaranteed that the
* selected sequence name won't conflict; given sufficiently long
* field names, two different serial columns in the same table could
* be assigned the same sequence name, and we'd not notice since we
* aren't creating the sequence quite yet. In practice this seems
* quite unlikely to be a problem, especially since few people would
* need two serial columns in one table.
*/
if (cxt->rel)
snamespaceid = RelationGetNamespace(cxt->rel);
else
snamespaceid = RangeVarGetCreationNamespace(cxt->relation);
snamespace = get_namespace_name(snamespaceid);
sname = ChooseRelationName(cxt->relation->relname,
column->colname,
"seq",
snamespaceid);
ereport(NOTICE,
(errmsg("%s will create implicit sequence \"%s\" for serial column \"%s.%s\"",
cxt->stmtType, sname,
cxt->relation->relname, column->colname)));
/*
* Build a CREATE SEQUENCE command to create the sequence object, and
* add it to the list of things to be done before this CREATE/ALTER
* TABLE.
*/
seqstmt = makeNode(CreateSeqStmt);
seqstmt->sequence = makeRangeVar(snamespace, sname);
seqstmt->options = NIL;
cxt->blist = lappend(cxt->blist, seqstmt);
/*
* Build an ALTER SEQUENCE ... OWNED BY command to mark the sequence
* as owned by this column, and add it to the list of things to be
* done after this CREATE/ALTER TABLE.
*/
altseqstmt = makeNode(AlterSeqStmt);
altseqstmt->sequence = makeRangeVar(snamespace, sname);
attnamelist = list_make3(makeString(snamespace),
makeString(cxt->relation->relname),
makeString(column->colname));
altseqstmt->options = list_make1(makeDefElem("owned_by",
(Node *) attnamelist));
cxt->alist = lappend(cxt->alist, altseqstmt);
/*
* Create appropriate constraints for SERIAL. We do this in full,
* rather than shortcutting, so that we will detect any conflicting
* constraints the user wrote (like a different DEFAULT).
*
* Create an expression tree representing the function call
* nextval('sequencename'). We cannot reduce the raw tree to cooked
* form until after the sequence is created, but there's no need to do
* so.
*/
qstring = quote_qualified_identifier(snamespace, sname);
snamenode = makeNode(A_Const);
snamenode->val.type = T_String;
snamenode->val.val.str = qstring;
snamenode->typename = SystemTypeName("regclass");
funccallnode = makeNode(FuncCall);
funccallnode->funcname = SystemFuncName("nextval");
funccallnode->args = list_make1(snamenode);
funccallnode->agg_star = false;
funccallnode->agg_distinct = false;
funccallnode->location = -1;
constraint = makeNode(Constraint);
constraint->contype = CONSTR_DEFAULT;
constraint->raw_expr = (Node *) funccallnode;
constraint->cooked_expr = NULL;
constraint->keys = NIL;
column->constraints = lappend(column->constraints, constraint);
constraint = makeNode(Constraint);
constraint->contype = CONSTR_NOTNULL;
column->constraints = lappend(column->constraints, constraint);
}
/* Process column constraints, if any... */
transformConstraintAttrs(column->constraints);
saw_nullable = false;
saw_default = false;
foreach(clist, column->constraints)
{
constraint = lfirst(clist);
/*
* If this column constraint is a FOREIGN KEY constraint, then we fill
* in the current attribute's name and throw it into the list of FK
* constraints to be processed later.
*/
if (IsA(constraint, FkConstraint))
{
FkConstraint *fkconstraint = (FkConstraint *) constraint;
fkconstraint->fk_attrs = list_make1(makeString(column->colname));
cxt->fkconstraints = lappend(cxt->fkconstraints, fkconstraint);
continue;
}
Assert(IsA(constraint, Constraint));
switch (constraint->contype)
{
case CONSTR_NULL:
if (saw_nullable && column->is_not_null)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
column->colname, cxt->relation->relname)));
column->is_not_null = FALSE;
saw_nullable = true;
break;
case CONSTR_NOTNULL:
if (saw_nullable && !column->is_not_null)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
column->colname, cxt->relation->relname)));
column->is_not_null = TRUE;
saw_nullable = true;
break;
case CONSTR_DEFAULT:
if (saw_default)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("multiple default values specified for column \"%s\" of table \"%s\"",
column->colname, cxt->relation->relname)));
/* Note: DEFAULT NULL maps to constraint->raw_expr == NULL */
column->raw_default = constraint->raw_expr;
Assert(constraint->cooked_expr == NULL);
saw_default = true;
break;
case CONSTR_PRIMARY:
case CONSTR_UNIQUE:
if (constraint->keys == NIL)
constraint->keys = list_make1(makeString(column->colname));
cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
break;
case CONSTR_CHECK:
cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
break;
case CONSTR_ATTR_DEFERRABLE:
case CONSTR_ATTR_NOT_DEFERRABLE:
case CONSTR_ATTR_DEFERRED:
case CONSTR_ATTR_IMMEDIATE:
/* transformConstraintAttrs took care of these */
break;
default:
elog(ERROR, "unrecognized constraint type: %d",
constraint->contype);
break;
}
}
}
/*
* transformTableConstraint
* transform a Constraint node within CREATE TABLE or ALTER TABLE
*/
static void
transformTableConstraint(ParseState *pstate, CreateStmtContext *cxt,
Constraint *constraint)
{
switch (constraint->contype)
{
case CONSTR_PRIMARY:
case CONSTR_UNIQUE:
cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
break;
case CONSTR_CHECK:
cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
break;
case CONSTR_NULL:
case CONSTR_NOTNULL:
case CONSTR_DEFAULT:
case CONSTR_ATTR_DEFERRABLE:
case CONSTR_ATTR_NOT_DEFERRABLE:
case CONSTR_ATTR_DEFERRED:
case CONSTR_ATTR_IMMEDIATE:
elog(ERROR, "invalid context for constraint type %d",
constraint->contype);
break;
default:
elog(ERROR, "unrecognized constraint type: %d",
constraint->contype);
break;
}
}
/*
* transformInhRelation
*
* Change the LIKE <subtable> portion of a CREATE TABLE statement into
* column definitions which recreate the user defined column portions of
* <subtable>.
*/
static void
transformInhRelation(ParseState *pstate, CreateStmtContext *cxt,
InhRelation *inhRelation)
{
AttrNumber parent_attno;
Relation relation;
TupleDesc tupleDesc;
TupleConstr *constr;
AclResult aclresult;
bool including_defaults = false;
bool including_constraints = false;
bool including_indexes = false;
ListCell *elem;
relation = heap_openrv(inhRelation->relation, AccessShareLock);
if (relation->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("inherited relation \"%s\" is not a table",
inhRelation->relation->relname)));
/*
* Check for SELECT privilages
*/
aclresult = pg_class_aclcheck(RelationGetRelid(relation), GetUserId(),
ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(relation));
tupleDesc = RelationGetDescr(relation);
constr = tupleDesc->constr;
foreach(elem, inhRelation->options)
{
int option = lfirst_int(elem);
switch (option)
{
case CREATE_TABLE_LIKE_INCLUDING_DEFAULTS:
including_defaults = true;
break;
case CREATE_TABLE_LIKE_EXCLUDING_DEFAULTS:
including_defaults = false;
break;
case CREATE_TABLE_LIKE_INCLUDING_CONSTRAINTS:
including_constraints = true;
break;
case CREATE_TABLE_LIKE_EXCLUDING_CONSTRAINTS:
including_constraints = false;
break;
case CREATE_TABLE_LIKE_INCLUDING_INDEXES:
including_indexes = true;
break;
case CREATE_TABLE_LIKE_EXCLUDING_INDEXES:
including_indexes = false;
break;
default:
elog(ERROR, "unrecognized CREATE TABLE LIKE option: %d",
option);
}
}
if (including_indexes)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("LIKE INCLUDING INDEXES is not implemented")));
/*
* Insert the copied attributes into the cxt for the new table
* definition.
*/
for (parent_attno = 1; parent_attno <= tupleDesc->natts;
parent_attno++)
{
Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
char *attributeName = NameStr(attribute->attname);
ColumnDef *def;
/*
* Ignore dropped columns in the parent.
*/
if (attribute->attisdropped)
continue;
/*
* Create a new column, which is marked as NOT inherited.
*
* For constraints, ONLY the NOT NULL constraint is inherited by the
* new column definition per SQL99.
*/
def = makeNode(ColumnDef);
def->colname = pstrdup(attributeName);
def->typename = makeTypeNameFromOid(attribute->atttypid,
attribute->atttypmod);
def->inhcount = 0;
def->is_local = true;
def->is_not_null = attribute->attnotnull;
def->raw_default = NULL;
def->cooked_default = NULL;
def->constraints = NIL;
/*
* Add to column list
*/
cxt->columns = lappend(cxt->columns, def);
/*
* Copy default, if present and the default has been requested
*/
if (attribute->atthasdef && including_defaults)
{
char *this_default = NULL;
AttrDefault *attrdef;
int i;
/* Find default in constraint structure */
Assert(constr != NULL);
attrdef = constr->defval;
for (i = 0; i < constr->num_defval; i++)
{
if (attrdef[i].adnum == parent_attno)
{
this_default = attrdef[i].adbin;
break;
}
}
Assert(this_default != NULL);
/*
* If default expr could contain any vars, we'd need to fix 'em,
* but it can't; so default is ready to apply to child.
*/
def->cooked_default = pstrdup(this_default);
}
}
/*
* Copy CHECK constraints if requested, being careful to adjust
* attribute numbers
*/
if (including_constraints && tupleDesc->constr)
{
AttrNumber *attmap = varattnos_map_schema(tupleDesc, cxt->columns);
int ccnum;
for (ccnum = 0; ccnum < tupleDesc->constr->num_check; ccnum++)
{
char *ccname = tupleDesc->constr->check[ccnum].ccname;
char *ccbin = tupleDesc->constr->check[ccnum].ccbin;
Node *ccbin_node = stringToNode(ccbin);
Constraint *n = makeNode(Constraint);
change_varattnos_of_a_node(ccbin_node, attmap);
n->contype = CONSTR_CHECK;
n->name = pstrdup(ccname);
n->raw_expr = NULL;
n->cooked_expr = nodeToString(ccbin_node);
n->indexspace = NULL;
cxt->ckconstraints = lappend(cxt->ckconstraints, (Node *) n);
}
}
/*
* Close the parent rel, but keep our AccessShareLock on it until xact
* commit. That will prevent someone else from deleting or ALTERing the
* parent before the child is committed.
*/
heap_close(relation, NoLock);
}
/*
* transformIndexConstraints
* Handle UNIQUE and PRIMARY KEY constraints, which create indexes
*/
static void
transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
{
IndexStmt *index;
List *indexlist = NIL;
ListCell *listptr;
ListCell *l;
/*
* Run through the constraints that need to generate an index. For PRIMARY
* KEY, mark each column as NOT NULL and create an index. For UNIQUE,
* create an index as for PRIMARY KEY, but do not insist on NOT NULL.
*/
foreach(listptr, cxt->ixconstraints)
{
Constraint *constraint = lfirst(listptr);
ListCell *keys;
IndexElem *iparam;
Assert(IsA(constraint, Constraint));
Assert((constraint->contype == CONSTR_PRIMARY)
|| (constraint->contype == CONSTR_UNIQUE));
index = makeNode(IndexStmt);
index->unique = true;
index->primary = (constraint->contype == CONSTR_PRIMARY);
if (index->primary)
{
if (cxt->pkey != NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("multiple primary keys for table \"%s\" are not allowed",
cxt->relation->relname)));
cxt->pkey = index;
/*
* In ALTER TABLE case, a primary index might already exist, but
* DefineIndex will check for it.
*/
}
index->isconstraint = true;
if (constraint->name != NULL)
index->idxname = pstrdup(constraint->name);
else
index->idxname = NULL; /* DefineIndex will choose name */
index->relation = cxt->relation;
index->accessMethod = DEFAULT_INDEX_TYPE;
index->options = constraint->options;
index->tableSpace = constraint->indexspace;
index->indexParams = NIL;
index->whereClause = NULL;
index->concurrent = false;
/*
* Make sure referenced keys exist. If we are making a PRIMARY KEY
* index, also make sure they are NOT NULL, if possible. (Although we
* could leave it to DefineIndex to mark the columns NOT NULL, it's
* more efficient to get it right the first time.)
*/
foreach(keys, constraint->keys)
{
char *key = strVal(lfirst(keys));
bool found = false;
ColumnDef *column = NULL;
ListCell *columns;
foreach(columns, cxt->columns)
{
column = (ColumnDef *) lfirst(columns);
Assert(IsA(column, ColumnDef));
if (strcmp(column->colname, key) == 0)
{
found = true;
break;
}
}
if (found)
{
/* found column in the new table; force it to be NOT NULL */
if (constraint->contype == CONSTR_PRIMARY)
column->is_not_null = TRUE;
}
else if (SystemAttributeByName(key, cxt->hasoids) != NULL)
{
/*
* column will be a system column in the new table, so accept
* it. System columns can't ever be null, so no need to worry
* about PRIMARY/NOT NULL constraint.
*/
found = true;
}
else if (cxt->inhRelations)
{
/* try inherited tables */
ListCell *inher;
foreach(inher, cxt->inhRelations)
{
RangeVar *inh = (RangeVar *) lfirst(inher);
Relation rel;
int count;
Assert(IsA(inh, RangeVar));
rel = heap_openrv(inh, AccessShareLock);
if (rel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("inherited relation \"%s\" is not a table",
inh->relname)));
for (count = 0; count < rel->rd_att->natts; count++)
{
Form_pg_attribute inhattr = rel->rd_att->attrs[count];
char *inhname = NameStr(inhattr->attname);
if (inhattr->attisdropped)
continue;
if (strcmp(key, inhname) == 0)
{
found = true;
/*
* We currently have no easy way to force an
* inherited column to be NOT NULL at creation, if
* its parent wasn't so already. We leave it to
* DefineIndex to fix things up in this case.
*/
break;
}
}
heap_close(rel, NoLock);
if (found)
break;
}
}
/*
* In the ALTER TABLE case, don't complain about index keys not
* created in the command; they may well exist already.
* DefineIndex will complain about them if not, and will also take
* care of marking them NOT NULL.
*/
if (!found && !cxt->isalter)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" named in key does not exist",
key)));
/* Check for PRIMARY KEY(foo, foo) */
foreach(columns, index->indexParams)
{
iparam = (IndexElem *) lfirst(columns);
if (iparam->name && strcmp(key, iparam->name) == 0)
{
if (index->primary)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" appears twice in primary key constraint",
key)));
else
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" appears twice in unique constraint",
key)));
}
}
/* OK, add it to the index definition */
iparam = makeNode(IndexElem);
iparam->name = pstrdup(key);
iparam->expr = NULL;
iparam->opclass = NIL;
iparam->ordering = SORTBY_DEFAULT;
iparam->nulls_ordering = SORTBY_NULLS_DEFAULT;
index->indexParams = lappend(index->indexParams, iparam);
}
indexlist = lappend(indexlist, index);
}
/*
* Scan the index list and remove any redundant index specifications. This
* can happen if, for instance, the user writes UNIQUE PRIMARY KEY. A
* strict reading of SQL92 would suggest raising an error instead, but
* that strikes me as too anal-retentive. - tgl 2001-02-14
*
* XXX in ALTER TABLE case, it'd be nice to look for duplicate
* pre-existing indexes, too.
*/
Assert(cxt->alist == NIL);
if (cxt->pkey != NULL)
{
/* Make sure we keep the PKEY index in preference to others... */
cxt->alist = list_make1(cxt->pkey);
}
foreach(l, indexlist)
{
bool keep = true;
ListCell *k;
index = lfirst(l);
/* if it's pkey, it's already in cxt->alist */
if (index == cxt->pkey)
continue;
foreach(k, cxt->alist)
{
IndexStmt *priorindex = lfirst(k);
if (equal(index->indexParams, priorindex->indexParams))
{
/*
* If the prior index is as yet unnamed, and this one is
* named, then transfer the name to the prior index. This
* ensures that if we have named and unnamed constraints,
* we'll use (at least one of) the names for the index.
*/
if (priorindex->idxname == NULL)
priorindex->idxname = index->idxname;
keep = false;
break;
}
}
if (keep)
cxt->alist = lappend(cxt->alist, index);
}
}
/*
* transformFKConstraints
* handle FOREIGN KEY constraints
*/
static void
transformFKConstraints(ParseState *pstate, CreateStmtContext *cxt,
bool skipValidation, bool isAddConstraint)
{
ListCell *fkclist;
if (cxt->fkconstraints == NIL)
return;
/*
* If CREATE TABLE or adding a column with NULL default, we can safely
* skip validation of the constraint.
*/
if (skipValidation)
{
foreach(fkclist, cxt->fkconstraints)
{
FkConstraint *fkconstraint = (FkConstraint *) lfirst(fkclist);
fkconstraint->skip_validation = true;
}
}
/*
* For CREATE TABLE or ALTER TABLE ADD COLUMN, gin up an ALTER TABLE ADD
* CONSTRAINT command to execute after the basic command is complete. (If
* called from ADD CONSTRAINT, that routine will add the FK constraints to
* its own subcommand list.)
*
* Note: the ADD CONSTRAINT command must also execute after any index
* creation commands. Thus, this should run after
* transformIndexConstraints, so that the CREATE INDEX commands are
* already in cxt->alist.
*/
if (!isAddConstraint)
{
AlterTableStmt *alterstmt = makeNode(AlterTableStmt);
alterstmt->relation = cxt->relation;
alterstmt->cmds = NIL;
alterstmt->relkind = OBJECT_TABLE;
foreach(fkclist, cxt->fkconstraints)
{
FkConstraint *fkconstraint = (FkConstraint *) lfirst(fkclist);
AlterTableCmd *altercmd = makeNode(AlterTableCmd);
altercmd->subtype = AT_ProcessedConstraint;
altercmd->name = NULL;
altercmd->def = (Node *) fkconstraint;
alterstmt->cmds = lappend(alterstmt->cmds, altercmd);
}
cxt->alist = lappend(cxt->alist, alterstmt);
}
}
/*
* transformIndexStmt - parse analysis for CREATE INDEX
*
* Note: this is a no-op for an index not using either index expressions or
* a predicate expression. There are several code paths that create indexes
* without bothering to call this, because they know they don't have any
* such expressions to deal with.
*/
IndexStmt *
transformIndexStmt(IndexStmt *stmt, const char *queryString)
{
Relation rel;
ParseState *pstate;
RangeTblEntry *rte;
ListCell *l;
/*
* We must not scribble on the passed-in IndexStmt, so copy it. (This
* is overkill, but easy.)
*/
stmt = (IndexStmt *) copyObject(stmt);
/*
* Open the parent table with appropriate locking. We must do this
* because addRangeTableEntry() would acquire only AccessShareLock,
* leaving DefineIndex() needing to do a lock upgrade with consequent
* risk of deadlock. Make sure this stays in sync with the type of
* lock DefineIndex() wants.
*/
rel = heap_openrv(stmt->relation,
(stmt->concurrent ? ShareUpdateExclusiveLock : ShareLock));
/* Set up pstate */
pstate = make_parsestate(NULL);
pstate->p_sourcetext = queryString;
/*
* Put the parent table into the rtable so that the expressions can
* refer to its fields without qualification.
*/
rte = addRangeTableEntry(pstate, stmt->relation, NULL, false, true);
/* no to join list, yes to namespaces */
addRTEtoQuery(pstate, rte, false, true, true);
/* take care of the where clause */
if (stmt->whereClause)
stmt->whereClause = transformWhereClause(pstate,
stmt->whereClause,
"WHERE");
/* take care of any index expressions */
foreach(l, stmt->indexParams)
{
IndexElem *ielem = (IndexElem *) lfirst(l);
if (ielem->expr)
{
ielem->expr = transformExpr(pstate, ielem->expr);
/*
* We check only that the result type is legitimate; this is for
* consistency with what transformWhereClause() checks for the
* predicate. DefineIndex() will make more checks.
*/
if (expression_returns_set(ielem->expr))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("index expression cannot return a set")));
}
}
/*
* Check that only the base rel is mentioned.
*/
if (list_length(pstate->p_rtable) != 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("index expressions and predicates can refer only to the table being indexed")));
free_parsestate(pstate);
/* Close relation, but keep the lock */
heap_close(rel, NoLock);
return stmt;
}
/*
* transformRuleStmt -
* transform a CREATE RULE Statement. The action is a list of parse
* trees which is transformed into a list of query trees, and we also
* transform the WHERE clause if any.
*
* actions and whereClause are output parameters that receive the
* transformed results.
*
* Note that we must not scribble on the passed-in RuleStmt, so we do
* copyObject() on the actions and WHERE clause.
*/
void
transformRuleStmt(RuleStmt *stmt, const char *queryString,
List **actions, Node **whereClause)
{
Relation rel;
ParseState *pstate;
RangeTblEntry *oldrte;
RangeTblEntry *newrte;
/*
* To avoid deadlock, make sure the first thing we do is grab
* AccessExclusiveLock on the target relation. This will be needed by
* DefineQueryRewrite(), and we don't want to grab a lesser lock
* beforehand.
*/
rel = heap_openrv(stmt->relation, AccessExclusiveLock);
/* Set up pstate */
pstate = make_parsestate(NULL);
pstate->p_sourcetext = queryString;
/*
* NOTE: 'OLD' must always have a varno equal to 1 and 'NEW' equal to 2.
* Set up their RTEs in the main pstate for use in parsing the rule
* qualification.
*/
oldrte = addRangeTableEntryForRelation(pstate, rel,
makeAlias("*OLD*", NIL),
false, false);
newrte = addRangeTableEntryForRelation(pstate, rel,
makeAlias("*NEW*", NIL),
false, false);
/* Must override addRangeTableEntry's default access-check flags */
oldrte->requiredPerms = 0;
newrte->requiredPerms = 0;
/*
* They must be in the namespace too for lookup purposes, but only add the
* one(s) that are relevant for the current kind of rule. In an UPDATE
* rule, quals must refer to OLD.field or NEW.field to be unambiguous, but
* there's no need to be so picky for INSERT & DELETE. We do not add them
* to the joinlist.
*/
switch (stmt->event)
{
case CMD_SELECT:
addRTEtoQuery(pstate, oldrte, false, true, true);
break;
case CMD_UPDATE:
addRTEtoQuery(pstate, oldrte, false, true, true);
addRTEtoQuery(pstate, newrte, false, true, true);
break;
case CMD_INSERT:
addRTEtoQuery(pstate, newrte, false, true, true);
break;
case CMD_DELETE:
addRTEtoQuery(pstate, oldrte, false, true, true);
break;
default:
elog(ERROR, "unrecognized event type: %d",
(int) stmt->event);
break;
}
/* take care of the where clause */
*whereClause = transformWhereClause(pstate,
(Node *) copyObject(stmt->whereClause),
"WHERE");
if (list_length(pstate->p_rtable) != 2) /* naughty, naughty... */
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("rule WHERE condition cannot contain references to other relations")));
/* aggregates not allowed (but subselects are okay) */
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in rule WHERE condition")));
/*
* 'instead nothing' rules with a qualification need a query 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 specially by the rewrite system.
*/
if (stmt->actions == NIL)
{
Query *nothing_qry = makeNode(Query);
nothing_qry->commandType = CMD_NOTHING;
nothing_qry->rtable = pstate->p_rtable;
nothing_qry->jointree = makeFromExpr(NIL, NULL); /* no join wanted */
*actions = list_make1(nothing_qry);
}
else
{
ListCell *l;
List *newactions = NIL;
/*
* transform each statement, like parse_sub_analyze()
*/
foreach(l, stmt->actions)
{
Node *action = (Node *) lfirst(l);
ParseState *sub_pstate = make_parsestate(NULL);
Query *sub_qry,
*top_subqry;
bool has_old,
has_new;
/*
* Since outer ParseState isn't parent of inner, have to pass
* down the query text by hand.
*/
sub_pstate->p_sourcetext = queryString;
/*
* Set up OLD/NEW in the rtable for this statement. The entries
* are added only to relnamespace, not varnamespace, because we
* don't want them to be referred to by unqualified field names
* nor "*" in the rule actions. We decide later whether to put
* them in the joinlist.
*/
oldrte = addRangeTableEntryForRelation(sub_pstate, rel,
makeAlias("*OLD*", NIL),
false, false);
newrte = addRangeTableEntryForRelation(sub_pstate, rel,
makeAlias("*NEW*", NIL),
false, false);
oldrte->requiredPerms = 0;
newrte->requiredPerms = 0;
addRTEtoQuery(sub_pstate, oldrte, false, true, false);
addRTEtoQuery(sub_pstate, newrte, false, true, false);
/* Transform the rule action statement */
top_subqry = transformStmt(sub_pstate,
(Node *) copyObject(action));
/*
* We cannot support utility-statement actions (eg NOTIFY) with
* nonempty rule WHERE conditions, because there's no way to make
* the utility action execute conditionally.
*/
if (top_subqry->commandType == CMD_UTILITY &&
*whereClause != NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("rules with WHERE conditions can only have SELECT, INSERT, UPDATE, or DELETE actions")));
/*
* If the action is INSERT...SELECT, OLD/NEW have been pushed down
* into the SELECT, and that's what we need to look at. (Ugly
* kluge ... try to fix this when we redesign querytrees.)
*/
sub_qry = getInsertSelectQuery(top_subqry, NULL);
/*
* If the sub_qry is a setop, we cannot attach any qualifications
* to it, because the planner won't notice them. This could
* perhaps be relaxed someday, but for now, we may as well reject
* such a rule immediately.
*/
if (sub_qry->setOperations != NULL && *whereClause != NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
/*
* Validate action's use of OLD/NEW, qual too
*/
has_old =
rangeTableEntry_used((Node *) sub_qry, PRS2_OLD_VARNO, 0) ||
rangeTableEntry_used(*whereClause, PRS2_OLD_VARNO, 0);
has_new =
rangeTableEntry_used((Node *) sub_qry, PRS2_NEW_VARNO, 0) ||
rangeTableEntry_used(*whereClause, PRS2_NEW_VARNO, 0);
switch (stmt->event)
{
case CMD_SELECT:
if (has_old)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("ON SELECT rule cannot use OLD")));
if (has_new)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("ON SELECT rule cannot use NEW")));
break;
case CMD_UPDATE:
/* both are OK */
break;
case CMD_INSERT:
if (has_old)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("ON INSERT rule cannot use OLD")));
break;
case CMD_DELETE:
if (has_new)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("ON DELETE rule cannot use NEW")));
break;
default:
elog(ERROR, "unrecognized event type: %d",
(int) stmt->event);
break;
}
/*
* For efficiency's sake, add OLD to the rule action's jointree
* only if it was actually referenced in the statement or qual.
*
* For INSERT, NEW is not really a relation (only a reference to
* the to-be-inserted tuple) and should never be added to the
* jointree.
*
* For UPDATE, we treat NEW as being another kind of reference to
* OLD, because it represents references to *transformed* tuples
* of the existing relation. It would be wrong to enter NEW
* separately in the jointree, since that would cause a double
* join of the updated relation. It's also wrong to fail to make
* a jointree entry if only NEW and not OLD is mentioned.
*/
if (has_old || (has_new && stmt->event == CMD_UPDATE))
{
/*
* If sub_qry is a setop, manipulating its jointree will do no
* good at all, because the jointree is dummy. (This should be
* a can't-happen case because of prior tests.)
*/
if (sub_qry->setOperations != NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
/* hack so we can use addRTEtoQuery() */
sub_pstate->p_rtable = sub_qry->rtable;
sub_pstate->p_joinlist = sub_qry->jointree->fromlist;
addRTEtoQuery(sub_pstate, oldrte, true, false, false);
sub_qry->jointree->fromlist = sub_pstate->p_joinlist;
}
newactions = lappend(newactions, top_subqry);
free_parsestate(sub_pstate);
}
*actions = newactions;
}
free_parsestate(pstate);
/* Close relation, but keep the exclusive lock */
heap_close(rel, NoLock);
}
/*
* transformAlterTableStmt -
* parse analysis for ALTER TABLE
*
* Returns a List of utility commands to be done in sequence. One of these
* will be the transformed AlterTableStmt, but there may be additional actions
* to be done before and after the actual AlterTable() call.
*/
List *
transformAlterTableStmt(AlterTableStmt *stmt, const char *queryString)
{
Relation rel;
ParseState *pstate;
CreateStmtContext cxt;
List *result;
List *save_alist;
ListCell *lcmd,
*l;
List *newcmds = NIL;
bool skipValidation = true;
AlterTableCmd *newcmd;
/*
* We must not scribble on the passed-in AlterTableStmt, so copy it.
* (This is overkill, but easy.)
*/
stmt = (AlterTableStmt *) copyObject(stmt);
/*
* Acquire exclusive lock on the target relation, which will be held
* until end of transaction. This ensures any decisions we make here
* based on the state of the relation will still be good at execution.
* We must get exclusive lock now because execution will; taking a lower
* grade lock now and trying to upgrade later risks deadlock.
*/
rel = relation_openrv(stmt->relation, AccessExclusiveLock);
/* Set up pstate */
pstate = make_parsestate(NULL);
pstate->p_sourcetext = queryString;
cxt.stmtType = "ALTER TABLE";
cxt.relation = stmt->relation;
cxt.rel = rel;
cxt.inhRelations = NIL;
cxt.isalter = true;
cxt.hasoids = false; /* need not be right */
cxt.columns = NIL;
cxt.ckconstraints = NIL;
cxt.fkconstraints = NIL;
cxt.ixconstraints = NIL;
cxt.blist = NIL;
cxt.alist = NIL;
cxt.pkey = NULL;
/*
* The only subtypes that currently require parse transformation handling
* are ADD COLUMN and ADD CONSTRAINT. These largely re-use code from
* CREATE TABLE.
*/
foreach(lcmd, stmt->cmds)
{
AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
switch (cmd->subtype)
{
case AT_AddColumn:
{
ColumnDef *def = (ColumnDef *) cmd->def;
Assert(IsA(cmd->def, ColumnDef));
transformColumnDefinition(pstate, &cxt,
(ColumnDef *) cmd->def);
/*
* If the column has a non-null default, we can't skip
* validation of foreign keys.
*/
if (((ColumnDef *) cmd->def)->raw_default != NULL)
skipValidation = false;
newcmds = lappend(newcmds, cmd);
/*
* Convert an ADD COLUMN ... NOT NULL constraint to a
* separate command
*/
if (def->is_not_null)
{
/* Remove NOT NULL from AddColumn */
def->is_not_null = false;
/* Add as a separate AlterTableCmd */
newcmd = makeNode(AlterTableCmd);
newcmd->subtype = AT_SetNotNull;
newcmd->name = pstrdup(def->colname);
newcmds = lappend(newcmds, newcmd);
}
/*
* All constraints are processed in other ways. Remove the
* original list
*/
def->constraints = NIL;
break;
}
case AT_AddConstraint:
/*
* The original AddConstraint cmd node doesn't go to newcmds
*/
if (IsA(cmd->def, Constraint))
transformTableConstraint(pstate, &cxt,
(Constraint *) cmd->def);
else if (IsA(cmd->def, FkConstraint))
{
cxt.fkconstraints = lappend(cxt.fkconstraints, cmd->def);
skipValidation = false;
}
else
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(cmd->def));
break;
case AT_ProcessedConstraint:
/*
* Already-transformed ADD CONSTRAINT, so just make it look
* like the standard case.
*/
cmd->subtype = AT_AddConstraint;
newcmds = lappend(newcmds, cmd);
break;
default:
newcmds = lappend(newcmds, cmd);
break;
}
}
/*
* transformIndexConstraints wants cxt.alist to contain only index
* statements, so transfer anything we already have into save_alist.
* immediately.
*/
save_alist = cxt.alist;
cxt.alist = NIL;
/* Postprocess index and FK constraints */
transformIndexConstraints(pstate, &cxt);
transformFKConstraints(pstate, &cxt, skipValidation, true);
/*
* Push any index-creation commands into the ALTER, so that they can be
* scheduled nicely by tablecmds.c. Note that tablecmds.c assumes that
* the IndexStmt attached to an AT_AddIndex subcommand has already been
* through transformIndexStmt.
*/
foreach(l, cxt.alist)
{
Node *idxstmt = (Node *) lfirst(l);
Assert(IsA(idxstmt, IndexStmt));
newcmd = makeNode(AlterTableCmd);
newcmd->subtype = AT_AddIndex;
newcmd->def = (Node *) transformIndexStmt((IndexStmt *) idxstmt,
queryString);
newcmds = lappend(newcmds, newcmd);
}
cxt.alist = NIL;
/* Append any CHECK or FK constraints to the commands list */
foreach(l, cxt.ckconstraints)
{
newcmd = makeNode(AlterTableCmd);
newcmd->subtype = AT_AddConstraint;
newcmd->def = (Node *) lfirst(l);
newcmds = lappend(newcmds, newcmd);
}
foreach(l, cxt.fkconstraints)
{
newcmd = makeNode(AlterTableCmd);
newcmd->subtype = AT_AddConstraint;
newcmd->def = (Node *) lfirst(l);
newcmds = lappend(newcmds, newcmd);
}
/* Close rel but keep lock */
relation_close(rel, NoLock);
/*
* Output results.
*/
stmt->cmds = newcmds;
result = lappend(cxt.blist, stmt);
result = list_concat(result, cxt.alist);
result = list_concat(result, save_alist);
return result;
}
/*
* Preprocess a list of column constraint clauses
* to attach constraint attributes to their primary constraint nodes
* and detect inconsistent/misplaced constraint attributes.
*
* NOTE: currently, attributes are only supported for FOREIGN KEY primary
* constraints, but someday they ought to be supported for other constraints.
*/
static void
transformConstraintAttrs(List *constraintList)
{
Node *lastprimarynode = NULL;
bool saw_deferrability = false;
bool saw_initially = false;
ListCell *clist;
foreach(clist, constraintList)
{
Node *node = lfirst(clist);
if (!IsA(node, Constraint))
{
lastprimarynode = node;
/* reset flags for new primary node */
saw_deferrability = false;
saw_initially = false;
}
else
{
Constraint *con = (Constraint *) node;
switch (con->contype)
{
case CONSTR_ATTR_DEFERRABLE:
if (lastprimarynode == NULL ||
!IsA(lastprimarynode, FkConstraint))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("misplaced DEFERRABLE clause")));
if (saw_deferrability)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("multiple DEFERRABLE/NOT DEFERRABLE clauses not allowed")));
saw_deferrability = true;
((FkConstraint *) lastprimarynode)->deferrable = true;
break;
case CONSTR_ATTR_NOT_DEFERRABLE:
if (lastprimarynode == NULL ||
!IsA(lastprimarynode, FkConstraint))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("misplaced NOT DEFERRABLE clause")));
if (saw_deferrability)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("multiple DEFERRABLE/NOT DEFERRABLE clauses not allowed")));
saw_deferrability = true;
((FkConstraint *) lastprimarynode)->deferrable = false;
if (saw_initially &&
((FkConstraint *) lastprimarynode)->initdeferred)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE")));
break;
case CONSTR_ATTR_DEFERRED:
if (lastprimarynode == NULL ||
!IsA(lastprimarynode, FkConstraint))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("misplaced INITIALLY DEFERRED clause")));
if (saw_initially)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("multiple INITIALLY IMMEDIATE/DEFERRED clauses not allowed")));
saw_initially = true;
((FkConstraint *) lastprimarynode)->initdeferred = true;
/*
* If only INITIALLY DEFERRED appears, assume DEFERRABLE
*/
if (!saw_deferrability)
((FkConstraint *) lastprimarynode)->deferrable = true;
else if (!((FkConstraint *) lastprimarynode)->deferrable)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("constraint declared INITIALLY DEFERRED must be DEFERRABLE")));
break;
case CONSTR_ATTR_IMMEDIATE:
if (lastprimarynode == NULL ||
!IsA(lastprimarynode, FkConstraint))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("misplaced INITIALLY IMMEDIATE clause")));
if (saw_initially)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("multiple INITIALLY IMMEDIATE/DEFERRED clauses not allowed")));
saw_initially = true;
((FkConstraint *) lastprimarynode)->initdeferred = false;
break;
default:
/* Otherwise it's not an attribute */
lastprimarynode = node;
/* reset flags for new primary node */
saw_deferrability = false;
saw_initially = false;
break;
}
}
}
}
/*
* Special handling of type definition for a column
*/
static void
transformColumnType(ParseState *pstate, ColumnDef *column)
{
/*
* All we really need to do here is verify that the type is valid.
*/
Type ctype = typenameType(pstate, column->typename);
ReleaseSysCache(ctype);
}
/*
* transformCreateSchemaStmt -
* analyzes the CREATE SCHEMA statement
*
* Split the schema element list into individual commands and place
* them in the result list in an order such that there are no forward
* references (e.g. GRANT to a table created later in the list). Note
* that the logic we use for determining forward references is
* presently quite incomplete.
*
* SQL92 also allows constraints to make forward references, so thumb through
* the table columns and move forward references to a posterior alter-table
* command.
*
* The result is a list of parse nodes that still need to be analyzed ---
* but we can't analyze the later commands until we've executed the earlier
* ones, because of possible inter-object references.
*
* Note: this breaks the rules a little bit by modifying schema-name fields
* within passed-in structs. However, the transformation would be the same
* if done over, so it should be all right to scribble on the input to this
* extent.
*/
List *
transformCreateSchemaStmt(CreateSchemaStmt *stmt)
{
CreateSchemaStmtContext cxt;
List *result;
ListCell *elements;
cxt.stmtType = "CREATE SCHEMA";
cxt.schemaname = stmt->schemaname;
cxt.authid = stmt->authid;
cxt.sequences = NIL;
cxt.tables = NIL;
cxt.views = NIL;
cxt.indexes = NIL;
cxt.triggers = NIL;
cxt.grants = NIL;
/*
* Run through each schema element in the schema element list. Separate
* statements by type, and do preliminary analysis.
*/
foreach(elements, stmt->schemaElts)
{
Node *element = lfirst(elements);
switch (nodeTag(element))
{
case T_CreateSeqStmt:
{
CreateSeqStmt *elp = (CreateSeqStmt *) element;
setSchemaName(cxt.schemaname, &elp->sequence->schemaname);
cxt.sequences = lappend(cxt.sequences, element);
}
break;
case T_CreateStmt:
{
CreateStmt *elp = (CreateStmt *) element;
setSchemaName(cxt.schemaname, &elp->relation->schemaname);
/*
* XXX todo: deal with constraints
*/
cxt.tables = lappend(cxt.tables, element);
}
break;
case T_ViewStmt:
{
ViewStmt *elp = (ViewStmt *) element;
setSchemaName(cxt.schemaname, &elp->view->schemaname);
/*
* XXX todo: deal with references between views
*/
cxt.views = lappend(cxt.views, element);
}
break;
case T_IndexStmt:
{
IndexStmt *elp = (IndexStmt *) element;
setSchemaName(cxt.schemaname, &elp->relation->schemaname);
cxt.indexes = lappend(cxt.indexes, element);
}
break;
case T_CreateTrigStmt:
{
CreateTrigStmt *elp = (CreateTrigStmt *) element;
setSchemaName(cxt.schemaname, &elp->relation->schemaname);
cxt.triggers = lappend(cxt.triggers, element);
}
break;
case T_GrantStmt:
cxt.grants = lappend(cxt.grants, element);
break;
default:
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(element));
}
}
result = NIL;
result = list_concat(result, cxt.sequences);
result = list_concat(result, cxt.tables);
result = list_concat(result, cxt.views);
result = list_concat(result, cxt.indexes);
result = list_concat(result, cxt.triggers);
result = list_concat(result, cxt.grants);
return result;
}
/*
* setSchemaName
* Set or check schema name in an element of a CREATE SCHEMA command
*/
static void
setSchemaName(char *context_schema, char **stmt_schema_name)
{
if (*stmt_schema_name == NULL)
*stmt_schema_name = context_schema;
else if (strcmp(context_schema, *stmt_schema_name) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_SCHEMA_DEFINITION),
errmsg("CREATE specifies a schema (%s) "
"different from the one being created (%s)",
*stmt_schema_name, context_schema)));
}