From a0c6dfeecfcc860858b04617a9d96eaee1d82c66 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 12 Mar 2013 17:37:07 -0400 Subject: [PATCH] Allow default expressions to be attached to columns of foreign tables. There's still some discussion about exactly how postgres_fdw ought to handle this case, but there seems no debate that we want to allow defaults to be used for inserts into foreign tables. So remove the core-code restrictions that prevented it. While at it, get rid of the special grammar productions for CREATE FOREIGN TABLE, and instead add explicit FEATURE_NOT_SUPPORTED error checks for the disallowed cases. This makes the grammar a shade smaller, and more importantly results in much more intelligible error messages for unsupported cases. It's also one less thing to fix if we ever start supporting constraints on foreign tables. --- doc/src/sgml/ref/alter_foreign_table.sgml | 19 +++++++- doc/src/sgml/ref/create_foreign_table.sgml | 31 +++++++++++- src/backend/commands/tablecmds.c | 14 +----- src/backend/parser/gram.y | 38 +++------------ src/backend/parser/parse_utilcmd.c | 57 ++++++++++++++++++++-- src/test/regress/expected/foreign_data.out | 21 ++++---- src/test/regress/sql/foreign_data.sql | 7 ++- 7 files changed, 123 insertions(+), 64 deletions(-) diff --git a/doc/src/sgml/ref/alter_foreign_table.sgml b/doc/src/sgml/ref/alter_foreign_table.sgml index f0b3129ab0..723aa075c5 100644 --- a/doc/src/sgml/ref/alter_foreign_table.sgml +++ b/doc/src/sgml/ref/alter_foreign_table.sgml @@ -32,9 +32,11 @@ ALTER FOREIGN TABLE [ IF EXISTS ] namewhere action is one of: - ADD [ COLUMN ] column_name data_type [ NULL | NOT NULL ] + ADD [ COLUMN ] column_name data_type [ COLLATE collation ] [ column_constraint [ ... ] ] DROP [ COLUMN ] [ IF EXISTS ] column_name [ RESTRICT | CASCADE ] ALTER [ COLUMN ] column_name [ SET DATA ] TYPE data_type + ALTER [ COLUMN ] column_name SET DEFAULT expression + ALTER [ COLUMN ] column_name DROP DEFAULT ALTER [ COLUMN ] column_name { SET | DROP } NOT NULL ALTER [ COLUMN ] column_name SET STATISTICS integer ALTER [ COLUMN ] column_name SET ( attribute_option = value [, ... ] ) @@ -59,6 +61,9 @@ ALTER FOREIGN TABLE [ IF EXISTS ] name This form adds a new column to the foreign table, using the same syntax as . + Unlike the case when adding a column to a regular table, nothing happens + to the underlying storage: this action simply declares that + some new column is now accessible through the foreign table. @@ -97,6 +102,18 @@ ALTER FOREIGN TABLE [ IF EXISTS ] name + + SET/DROP DEFAULT + + + These forms set or remove the default value for a column. + Default values only apply in subsequent INSERT + or UPDATE commands; they do not cause rows already in the + table to change. + + + + SET/DROP NOT NULL diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml index 0a6ac29d4d..1ef4b5e9d7 100644 --- a/doc/src/sgml/ref/create_foreign_table.sgml +++ b/doc/src/sgml/ref/create_foreign_table.sgml @@ -19,12 +19,18 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] table_name ( [ - { column_name data_type [ OPTIONS ( option 'value' [, ... ] ) ] [ NULL | NOT NULL ] } + column_name data_type [ OPTIONS ( option 'value' [, ... ] ) ] [ COLLATE collation ] [ column_constraint [ ... ] ] [, ... ] ] ) SERVER server_name [ OPTIONS ( option 'value' [, ... ] ) ] +where column_constraint is: + +[ CONSTRAINT constraint_name ] +{ NOT NULL | + NULL | + DEFAULT default_expr } @@ -131,6 +137,27 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] table_name + + DEFAULT + default_expr + + + The DEFAULT clause assigns a default data value for + the column whose column definition it appears within. The value + is any variable-free expression (subqueries and cross-references + to other columns in the current table are not allowed). The + data type of the default expression must match the data type of the + column. + + + + The default expression will be used in any insert operation that + does not specify a value for the column. If there is no default + for a column, then the default is null. + + + + server_name @@ -190,6 +217,8 @@ SERVER film_server; SQL standard; however, much as with CREATE TABLE, NULL constraints and zero-column foreign tables are permitted. + The ability to specify a default value is also a PostgreSQL + extension. diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 47b6233a80..8bb8f54ae5 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -465,7 +465,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId) if (stmt->constraints != NIL && relkind == RELKIND_FOREIGN_TABLE) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), - errmsg("constraints on foreign tables are not supported"))); + errmsg("constraints are not supported on foreign tables"))); /* * Look up the namespace in which we are supposed to create the relation, @@ -588,11 +588,6 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId) { RawColumnDefault *rawEnt; - if (relkind == RELKIND_FOREIGN_TABLE) - ereport(ERROR, - (errcode(ERRCODE_WRONG_OBJECT_TYPE), - errmsg("default values on foreign tables are not supported"))); - Assert(colDef->cooked_default == NULL); rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault)); @@ -2978,7 +2973,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd, * substitutes default values into INSERTs before it expands * rules. */ - ATSimplePermissions(rel, ATT_TABLE | ATT_VIEW); + ATSimplePermissions(rel, ATT_TABLE | ATT_VIEW | ATT_FOREIGN_TABLE); ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode); /* No command-specific prep needed */ pass = cmd->def ? AT_PASS_ADD_CONSTR : AT_PASS_DROP; @@ -4528,11 +4523,6 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel, { RawColumnDefault *rawEnt; - if (relkind == RELKIND_FOREIGN_TABLE) - ereport(ERROR, - (errcode(ERRCODE_WRONG_OBJECT_TYPE), - errmsg("default values on foreign tables are not supported"))); - rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault)); rawEnt->attnum = attribute.attnum; rawEnt->raw_default = copyObject(colDef->raw_default); diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 0787d2f506..9d07f30906 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -330,7 +330,6 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); %type stmtblock stmtmulti OptTableElementList TableElementList OptInherit definition OptTypedTableElementList TypedTableElementList - OptForeignTableElementList ForeignTableElementList reloptions opt_reloptions OptWith opt_distinct opt_definition func_args func_args_list func_args_with_defaults func_args_with_defaults_list @@ -408,7 +407,6 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); %type set_rest set_rest_more SetResetClause FunctionSetResetClause %type TableElement TypedTableElement ConstraintElem TableFuncElement - ForeignTableElement %type columnDef columnOptions %type def_elem reloption_elem old_aggr_elem %type def_arg columnElem where_clause where_or_current_clause @@ -4137,57 +4135,37 @@ AlterForeignServerStmt: ALTER SERVER name foreign_server_version alter_generic_o CreateForeignTableStmt: CREATE FOREIGN TABLE qualified_name - OptForeignTableElementList + '(' OptTableElementList ')' SERVER name create_generic_options { CreateForeignTableStmt *n = makeNode(CreateForeignTableStmt); $4->relpersistence = RELPERSISTENCE_PERMANENT; n->base.relation = $4; - n->base.tableElts = $5; + n->base.tableElts = $6; n->base.inhRelations = NIL; n->base.if_not_exists = false; /* FDW-specific data */ - n->servername = $7; - n->options = $8; + n->servername = $9; + n->options = $10; $$ = (Node *) n; } | CREATE FOREIGN TABLE IF_P NOT EXISTS qualified_name - OptForeignTableElementList + '(' OptTableElementList ')' SERVER name create_generic_options { CreateForeignTableStmt *n = makeNode(CreateForeignTableStmt); $7->relpersistence = RELPERSISTENCE_PERMANENT; n->base.relation = $7; - n->base.tableElts = $8; + n->base.tableElts = $9; n->base.inhRelations = NIL; n->base.if_not_exists = true; /* FDW-specific data */ - n->servername = $10; - n->options = $11; + n->servername = $12; + n->options = $13; $$ = (Node *) n; } ; -OptForeignTableElementList: - '(' ForeignTableElementList ')' { $$ = $2; } - | '(' ')' { $$ = NIL; } - ; - -ForeignTableElementList: - ForeignTableElement - { - $$ = list_make1($1); - } - | ForeignTableElementList ',' ForeignTableElement - { - $$ = lappend($1, $3); - } - ; - -ForeignTableElement: - columnDef { $$ = $1; } - ; - /***************************************************************************** * * QUERY: diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c index 8a1876c8a3..4fdcf180fa 100644 --- a/src/backend/parser/parse_utilcmd.c +++ b/src/backend/parser/parse_utilcmd.c @@ -70,6 +70,7 @@ typedef struct RangeVar *relation; /* relation to create */ Relation rel; /* opened/locked rel, if ALTER */ List *inhRelations; /* relations to inherit from */ + bool isforeign; /* true if CREATE/ALTER FOREIGN TABLE */ bool isalter; /* true if altering existing table */ bool hasoids; /* does relation have an OID column? */ List *columns; /* ColumnDef items */ @@ -195,9 +196,15 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString) cxt.pstate = pstate; if (IsA(stmt, CreateForeignTableStmt)) + { cxt.stmtType = "CREATE FOREIGN TABLE"; + cxt.isforeign = true; + } else + { cxt.stmtType = "CREATE TABLE"; + cxt.isforeign = false; + } cxt.relation = stmt->relation; cxt.rel = NULL; cxt.inhRelations = stmt->inhRelations; @@ -515,11 +522,23 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column) break; case CONSTR_CHECK: + if (cxt->isforeign) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("constraints are not supported on foreign tables"), + parser_errposition(cxt->pstate, + constraint->location))); cxt->ckconstraints = lappend(cxt->ckconstraints, constraint); break; case CONSTR_PRIMARY: case CONSTR_UNIQUE: + if (cxt->isforeign) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("constraints are not supported on foreign tables"), + parser_errposition(cxt->pstate, + constraint->location))); if (constraint->keys == NIL) constraint->keys = list_make1(makeString(column->colname)); cxt->ixconstraints = lappend(cxt->ixconstraints, constraint); @@ -531,7 +550,12 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column) break; case CONSTR_FOREIGN: - + if (cxt->isforeign) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("constraints are not supported on foreign tables"), + parser_errposition(cxt->pstate, + constraint->location))); /* * Fill in the current attribute's name and throw it into the * list of FK constraints to be processed later. @@ -555,8 +579,8 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column) } /* - * Generate ALTER FOREIGN TABLE ALTER COLUMN statement which adds - * per-column foreign data wrapper options for this column. + * If needed, generate ALTER FOREIGN TABLE ALTER COLUMN statement to add + * per-column foreign data wrapper options to this column after creation. */ if (column->fdwoptions != NIL) { @@ -587,6 +611,13 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column) static void transformTableConstraint(CreateStmtContext *cxt, Constraint *constraint) { + if (cxt->isforeign) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("constraints are not supported on foreign tables"), + parser_errposition(cxt->pstate, + constraint->location))); + switch (constraint->contype) { case CONSTR_PRIMARY: @@ -640,7 +671,14 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla char *comment; ParseCallbackState pcbstate; - setup_parser_errposition_callback(&pcbstate, cxt->pstate, table_like_clause->relation->location); + setup_parser_errposition_callback(&pcbstate, cxt->pstate, + table_like_clause->relation->location); + + /* we could support LIKE in many cases, but worry about it another day */ + if (cxt->isforeign) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("LIKE is not supported for foreign tables"))); relation = relation_openrv(table_like_clause->relation, AccessShareLock); @@ -2334,7 +2372,16 @@ transformAlterTableStmt(AlterTableStmt *stmt, const char *queryString) pstate->p_sourcetext = queryString; cxt.pstate = pstate; - cxt.stmtType = "ALTER TABLE"; + if (stmt->relkind == OBJECT_FOREIGN_TABLE) + { + cxt.stmtType = "ALTER FOREIGN TABLE"; + cxt.isforeign = true; + } + else + { + cxt.stmtType = "ALTER TABLE"; + cxt.isforeign = false; + } cxt.relation = stmt->relation; cxt.rel = rel; cxt.inhRelations = NIL; diff --git a/src/test/regress/expected/foreign_data.out b/src/test/regress/expected/foreign_data.out index 1bfdca134b..60506e07b1 100644 --- a/src/test/regress/expected/foreign_data.out +++ b/src/test/regress/expected/foreign_data.out @@ -664,8 +664,6 @@ LINE 1: CREATE FOREIGN TABLE ft1 (); ^ CREATE FOREIGN TABLE ft1 () SERVER no_server; -- ERROR ERROR: server "no_server" does not exist -CREATE FOREIGN TABLE ft1 (c1 serial) SERVER sc; -- ERROR -ERROR: default values on foreign tables are not supported CREATE FOREIGN TABLE ft1 () SERVER s0 WITH OIDS; -- ERROR ERROR: syntax error at or near "WITH OIDS" LINE 1: CREATE FOREIGN TABLE ft1 () SERVER s0 WITH OIDS; @@ -707,17 +705,14 @@ COMMENT ON FOREIGN TABLE ft1 IS NULL; COMMENT ON COLUMN ft1.c1 IS 'foreign column'; COMMENT ON COLUMN ft1.c1 IS NULL; ALTER FOREIGN TABLE ft1 ADD COLUMN c4 integer; -ALTER FOREIGN TABLE ft1 ADD COLUMN c5 integer DEFAULT 0; -- ERROR -ERROR: default values on foreign tables are not supported +ALTER FOREIGN TABLE ft1 ADD COLUMN c5 integer DEFAULT 0; ALTER FOREIGN TABLE ft1 ADD COLUMN c6 integer; ALTER FOREIGN TABLE ft1 ADD COLUMN c7 integer NOT NULL; ALTER FOREIGN TABLE ft1 ADD COLUMN c8 integer; ALTER FOREIGN TABLE ft1 ADD COLUMN c9 integer; ALTER FOREIGN TABLE ft1 ADD COLUMN c10 integer OPTIONS (p1 'v1'); -ALTER FOREIGN TABLE ft1 ALTER COLUMN c4 SET DEFAULT 0; -- ERROR -ERROR: "ft1" is not a table or view -ALTER FOREIGN TABLE ft1 ALTER COLUMN c5 DROP DEFAULT; -- ERROR -ERROR: "ft1" is not a table or view +ALTER FOREIGN TABLE ft1 ALTER COLUMN c4 SET DEFAULT 0; +ALTER FOREIGN TABLE ft1 ALTER COLUMN c5 DROP DEFAULT; ALTER FOREIGN TABLE ft1 ALTER COLUMN c6 SET NOT NULL; ALTER FOREIGN TABLE ft1 ALTER COLUMN c7 DROP NOT NULL; ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE char(10) USING '0'; -- ERROR @@ -739,7 +734,8 @@ ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STATISTICS -1; c1 | integer | not null | ("param 1" 'val1') | plain | 10000 | c2 | text | | (param2 'val2', param3 'val3') | extended | | c3 | date | | | plain | | - c4 | integer | | | plain | | + c4 | integer | default 0 | | plain | | + c5 | integer | | | plain | | c6 | integer | not null | | plain | | c7 | integer | | (p1 'v1', p2 'v2') | plain | | c8 | text | | (p2 'V2') | extended | | @@ -755,7 +751,9 @@ ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET DATA TYPE integer; -- ERROR ERROR: cannot alter foreign table "ft1" because column "use_ft1_column_type.x" uses its row type DROP TABLE use_ft1_column_type; ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c9 < 0); -- ERROR -ERROR: "ft1" is not a table +ERROR: constraints are not supported on foreign tables +LINE 1: ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c9_check CHECK (c... + ^ ALTER FOREIGN TABLE ft1 DROP CONSTRAINT no_const; -- ERROR ERROR: "ft1" is not a table ALTER FOREIGN TABLE ft1 DROP CONSTRAINT IF EXISTS no_const; @@ -783,7 +781,8 @@ ALTER FOREIGN TABLE foreign_schema.ft1 RENAME TO foreign_table_1; foreign_column_1 | integer | not null | ("param 1" 'val1') c2 | text | | (param2 'val2', param3 'val3') c3 | date | | - c4 | integer | | + c4 | integer | default 0 | + c5 | integer | | c6 | integer | not null | c7 | integer | | (p1 'v1', p2 'v2') c8 | text | | (p2 'V2') diff --git a/src/test/regress/sql/foreign_data.sql b/src/test/regress/sql/foreign_data.sql index 38057db7b4..f819eb1b8e 100644 --- a/src/test/regress/sql/foreign_data.sql +++ b/src/test/regress/sql/foreign_data.sql @@ -267,7 +267,6 @@ CREATE SCHEMA foreign_schema; CREATE SERVER s0 FOREIGN DATA WRAPPER dummy; CREATE FOREIGN TABLE ft1 (); -- ERROR CREATE FOREIGN TABLE ft1 () SERVER no_server; -- ERROR -CREATE FOREIGN TABLE ft1 (c1 serial) SERVER sc; -- ERROR CREATE FOREIGN TABLE ft1 () SERVER s0 WITH OIDS; -- ERROR CREATE FOREIGN TABLE ft1 ( c1 integer OPTIONS ("param 1" 'val1') NOT NULL, @@ -289,15 +288,15 @@ COMMENT ON COLUMN ft1.c1 IS 'foreign column'; COMMENT ON COLUMN ft1.c1 IS NULL; ALTER FOREIGN TABLE ft1 ADD COLUMN c4 integer; -ALTER FOREIGN TABLE ft1 ADD COLUMN c5 integer DEFAULT 0; -- ERROR +ALTER FOREIGN TABLE ft1 ADD COLUMN c5 integer DEFAULT 0; ALTER FOREIGN TABLE ft1 ADD COLUMN c6 integer; ALTER FOREIGN TABLE ft1 ADD COLUMN c7 integer NOT NULL; ALTER FOREIGN TABLE ft1 ADD COLUMN c8 integer; ALTER FOREIGN TABLE ft1 ADD COLUMN c9 integer; ALTER FOREIGN TABLE ft1 ADD COLUMN c10 integer OPTIONS (p1 'v1'); -ALTER FOREIGN TABLE ft1 ALTER COLUMN c4 SET DEFAULT 0; -- ERROR -ALTER FOREIGN TABLE ft1 ALTER COLUMN c5 DROP DEFAULT; -- ERROR +ALTER FOREIGN TABLE ft1 ALTER COLUMN c4 SET DEFAULT 0; +ALTER FOREIGN TABLE ft1 ALTER COLUMN c5 DROP DEFAULT; ALTER FOREIGN TABLE ft1 ALTER COLUMN c6 SET NOT NULL; ALTER FOREIGN TABLE ft1 ALTER COLUMN c7 DROP NOT NULL; ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE char(10) USING '0'; -- ERROR