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Ban some useage of ROWNUM

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1.Ban ROWNUM in INSERT...VALUES（） STATEMENT
2.Ban ROWNUM after DEFAULT when creating table
3.Ban ROWNUM in VALUES clause that's being used as a standalone SELECT like select * from (values(rownum,1)), x(a,b)
This commit is contained in:
zhouxiongjia
2020-08-14 14:24:01 +08:00
parent 2962e03482
commit c9738b11d1
6 changed files with 65 additions and 5 deletions
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8
src/common/backend/catalog/heap.cpp
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@ -3442,11 +3442,17 @@ Node* cookDefault(ParseState* pstate, Node* raw_default, Oid atttypid, int32 att
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE), errmsg("cannot use column references in default expression")));
/*
* Make sure default expr does not refer to rownum.
*/
ExcludeRownumExpr(pstate, expr);
/*
* It can't return a set either.
*/
if (expression_returns_set(expr))
ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("default expression must not return a set")));
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("default expression must not return a set")));
/*
* No subplans or aggregates, either...

3
src/common/backend/nodes/nodeFuncs.cpp
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@ -1383,6 +1383,9 @@ int exprLocation(const Node* expr)
/* just use typename's location */
loc = exprLocation((Node*)((const FunctionParameter*)expr)->argType);
break;
case T_Rownum:
loc = ((const Rownum*)expr)->location;
break;
default:
/* for any other node type it's just unknown... */
loc = -1;

14
src/common/backend/parser/analyze.cpp
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@ -1536,6 +1536,10 @@ List* transformInsertRow(ParseState* pstate, List* exprlist, List* stmtcols, Lis
foreach (lc, exprlist) {
Expr* expr = (Expr*)lfirst(lc);
ResTarget* col = NULL;
/*
* Rownum is not allowed in exprlist in INSERT statement.
*/
ExcludeRownumExpr(pstate, (Node*)expr);
col = (ResTarget*)lfirst(icols);
AssertEreport(IsA(col, ResTarget), MOD_OPT, "nodeType inconsistant");
@ -1802,7 +1806,7 @@ static Query* transformValuesClause(ParseState* pstate, SelectStmt* stmt)
/*
* For each row of VALUES, transform the raw expressions. This is also a
* handy place to reject DEFAULT nodes, which the grammar allows for
* handy place to reject DEFAULT nodes and Rownum, which the grammar allows for
* simplicity.
*
* Note that the intermediate representation we build is column-organized
@ -1832,7 +1836,7 @@ static Query* transformValuesClause(ParseState* pstate, SelectStmt* stmt)
parser_errposition(pstate, exprLocation((Node*)sublist))));
}
/* Check for DEFAULT and build per-column expression lists */
/* Check for DEFAULT and Rownum, then build per-column expression lists */
i = 0;
foreach (lc2, sublist) {
Node* col = (Node*)lfirst(lc2);
@ -1842,9 +1846,13 @@ static Query* transformValuesClause(ParseState* pstate, SelectStmt* stmt)
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("DEFAULT can only appear in a VALUES list within INSERT"),
parser_errposition(pstate, exprLocation(col))));
}
}
ExcludeRownumExpr(pstate, col);
colexprs[i] = lappend(colexprs[i], col);
i++;
}
/* Release sub-list's cells to save memory */

12
src/include/optimizer/clauses.h
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@ -15,6 +15,8 @@
#define CLAUSES_H
#include "nodes/relation.h"
#include "parser/parse_node.h"
#include "nodes/nodeFuncs.h"
#define is_opclause(clause) ((clause) != NULL && IsA(clause, OpExpr))
#define is_funcclause(clause) ((clause) != NULL && IsA(clause, FuncExpr))
@ -112,6 +114,16 @@ static inline bool contain_rownum_expr(Node *node)
return contain_rownum_walker(node, NULL);
}
/* Check if it includes Rownum */
static inline void ExcludeRownumExpr(ParseState* pstate, Node* expr)
{
if (contain_rownum_expr(expr))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("specified ROWNUM is not allowed here."),
parser_errposition(pstate, exprLocation(expr))));
}
extern List* get_quals_lists(Node *jtnode);
#endif /* CLAUSES_H */

24
src/test/regress/expected/xc_rownum.out
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@ -251,7 +251,29 @@ select rownum rowno2, * from (select rownum rowno1, * from distributors order by
ERROR: Alias "rowno2" reference with ROWNUM included is invalid.
LINE 1: ...wno1, * from distributors order by id desc) where rowno2 < 2...
^
--test default rownum when creating table
create table student(id int default rownum, stuname varchar(5));
ERROR: specified ROWNUM is not allowed here.
create table student(id int default rownum+1, stuname varchar(5));
ERROR: specified ROWNUM is not allowed here.
--test insert when values include rownum
insert into distributors values (rownum, 'qwer');
ERROR: specified ROWNUM is not allowed here.
LINE 1: insert into distributors values (rownum, 'qwer');
^
insert into distributors(id, name) values (2, 'abcd'), (rownum+1, 'qwer');
ERROR: specified ROWNUM is not allowed here.
LINE 1: ... into distributors(id, name) values (2, 'abcd'), (rownum+1, ...
^
--test VALUES clause that's being used as a standalone SELECT
select * from (values(rownum, 1)) x(a, b);
ERROR: specified ROWNUM is not allowed here.
LINE 1: select * from (values(rownum, 1)) x(a, b);
^
select * from (values(rownum+1, 1)) x(a, b);
ERROR: specified ROWNUM is not allowed here.
LINE 1: select * from (values(rownum+1, 1)) x(a, b);
^
--test except and minus
--create test table
create table except_table (a int, b int);

9
src/test/regress/sql/xc_rownum.sql
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@ -88,6 +88,15 @@ select rownum + 1 rn from dual group by rn;
--test alias name after where
select rownum rn, name from distributors where rn<3;
select rownum rowno2, * from (select rownum rowno1, * from distributors order by id desc) where rowno2 < 2;
--test default rownum when creating table
create table student(id int default rownum, stuname varchar(5));
create table student(id int default rownum+1, stuname varchar(5));
--test insert when values include rownum
insert into distributors values (rownum, 'qwer');
insert into distributors(id, name) values (2, 'abcd'), (rownum+1, 'qwer');
--test VALUES clause that's being used as a standalone SELECT
select * from (values(rownum, 1)) x(a, b);
select * from (values(rownum+1, 1)) x(a, b);
--test except and minus
--create test table