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Provide FORCE_NULL * and FORCE_NOT_NULL * options for COPY FROM

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These options already exist, but you need to specify a column list for
them, which can be cumbersome. We already have the possibility of all
columns for FORCE QUOTE, so this is simply extending that facility to
FORCE_NULL and FORCE_NOT_NULL.

Author: Zhang Mingli
Reviewed-By: Richard Guo, Kyatoro Horiguchi, Michael Paquier.

Discussion: https://postgr.es/m/CACJufxEnVqzOFtqhexF2+AwOKFrV8zHOY3y=p+gPK6eB14pn_w@mail.gmail.com
This commit is contained in:
Andrew Dunstan 2023-09-30 12:34:41 -04:00
parent c181f2e2bc
commit f6d4c9cf16
8 changed files with 103 additions and 12 deletions
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6
doc/src/sgml/ref/copy.sgml
View File

@ -41,8 +41,8 @@ COPY { <replaceable class="parameter">table_name</replaceable> [ ( <replaceable
QUOTE '<replaceable class="parameter">quote_character</replaceable>'
ESCAPE '<replaceable class="parameter">escape_character</replaceable>'
FORCE_QUOTE { ( <replaceable class="parameter">column_name</replaceable> [, ...] ) | * }
FORCE_NOT_NULL ( <replaceable class="parameter">column_name</replaceable> [, ...] )
FORCE_NULL ( <replaceable class="parameter">column_name</replaceable> [, ...] )
FORCE_NOT_NULL { ( <replaceable class="parameter">column_name</replaceable> [, ...] ) | * }
FORCE_NULL { ( <replaceable class="parameter">column_name</replaceable> [, ...] ) | * }
ENCODING '<replaceable class="parameter">encoding_name</replaceable>'
</synopsis>
</refsynopsisdiv>
@ -350,6 +350,7 @@ COPY { <replaceable class="parameter">table_name</replaceable> [ ( <replaceable
In the default case where the null string is empty, this means that
empty values will be read as zero-length strings rather than nulls,
even when they are not quoted.
If <literal>*</literal> is specified, the option will be applied to all columns.
This option is allowed only in <command>COPY FROM</command>, and only when
using <literal>CSV</literal> format.
</para>
@ -364,6 +365,7 @@ COPY { <replaceable class="parameter">table_name</replaceable> [ ( <replaceable
if it has been quoted, and if a match is found set the value to
<literal>NULL</literal>. In the default case where the null string is empty,
this converts a quoted empty string into NULL.
If <literal>*</literal> is specified, the option will be applied to all columns.
This option is allowed only in <command>COPY FROM</command>, and only when
using <literal>CSV</literal> format.
</para>

12
src/backend/commands/copy.c
View File

@ -512,9 +512,11 @@ ProcessCopyOptions(ParseState *pstate,
}
else if (strcmp(defel->defname, "force_not_null") == 0)
{
if (opts_out->force_notnull)
if (opts_out->force_notnull || opts_out->force_notnull_all)
errorConflictingDefElem(defel, pstate);
if (defel->arg && IsA(defel->arg, List))
if (defel->arg && IsA(defel->arg, A_Star))
opts_out->force_notnull_all = true;
else if (defel->arg && IsA(defel->arg, List))
opts_out->force_notnull = castNode(List, defel->arg);
else
ereport(ERROR,
@ -525,9 +527,11 @@ ProcessCopyOptions(ParseState *pstate,
}
else if (strcmp(defel->defname, "force_null") == 0)
{
if (opts_out->force_null)
if (opts_out->force_null || opts_out->force_null_all)
errorConflictingDefElem(defel, pstate);
if (defel->arg && IsA(defel->arg, List))
if (defel->arg && IsA(defel->arg, A_Star))
opts_out->force_null_all = true;
else if (defel->arg && IsA(defel->arg, List))
opts_out->force_null = castNode(List, defel->arg);
else
ereport(ERROR,

8
src/backend/commands/copyfrom.c
View File

@ -1393,7 +1393,9 @@ BeginCopyFrom(ParseState *pstate,
/* Convert FORCE_NOT_NULL name list to per-column flags, check validity */
cstate->opts.force_notnull_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
if (cstate->opts.force_notnull)
if (cstate->opts.force_notnull_all)
MemSet(cstate->opts.force_notnull_flags, true, num_phys_attrs * sizeof(bool));
else if (cstate->opts.force_notnull)
{
List *attnums;
ListCell *cur;
@ -1416,7 +1418,9 @@ BeginCopyFrom(ParseState *pstate,
/* Convert FORCE_NULL name list to per-column flags, check validity */
cstate->opts.force_null_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
if (cstate->opts.force_null)
if (cstate->opts.force_null_all)
MemSet(cstate->opts.force_null_flags, true, num_phys_attrs * sizeof(bool));
else if (cstate->opts.force_null)
{
List *attnums;
ListCell *cur;

5
src/backend/commands/copyto.c
View File

@ -582,10 +582,7 @@ BeginCopyTo(ParseState *pstate,
cstate->opts.force_quote_flags = (bool *) palloc0(num_phys_attrs * sizeof(bool));
if (cstate->opts.force_quote_all)
{
int i;
for (i = 0; i < num_phys_attrs; i++)
cstate->opts.force_quote_flags[i] = true;
MemSet(cstate->opts.force_quote_flags, true, num_phys_attrs * sizeof(bool));
}
else if (cstate->opts.force_quote)
{

8
src/backend/parser/gram.y
View File

@ -3419,10 +3419,18 @@ copy_opt_item:
{
$$ = makeDefElem("force_not_null", (Node *) $4, @1);
}
| FORCE NOT NULL_P '*'
{
$$ = makeDefElem("force_not_null", (Node *) makeNode(A_Star), @1);
}
| FORCE NULL_P columnList
{
$$ = makeDefElem("force_null", (Node *) $3, @1);
}
| FORCE NULL_P '*'
{
$$ = makeDefElem("force_null", (Node *) makeNode(A_Star), @1);
}
| ENCODING Sconst
{
$$ = makeDefElem("encoding", (Node *) makeString($2), @1);

2
src/include/commands/copy.h
View File

@ -56,8 +56,10 @@ typedef struct CopyFormatOptions
bool force_quote_all; /* FORCE_QUOTE *? */
bool *force_quote_flags; /* per-column CSV FQ flags */
List *force_notnull; /* list of column names */
bool force_notnull_all; /* FORCE_NOT_NULL *? */
bool *force_notnull_flags; /* per-column CSV FNN flags */
List *force_null; /* list of column names */
bool force_null_all; /* FORCE_NULL *? */
bool *force_null_flags; /* per-column CSV FN flags */
bool convert_selectively; /* do selective binary conversion? */
List *convert_select; /* list of column names (can be NIL) */

44
src/test/regress/expected/copy2.out
View File

@ -520,6 +520,50 @@ BEGIN;
COPY forcetest (d, e) FROM STDIN WITH (FORMAT csv, FORCE_NULL(b));
ERROR: FORCE_NULL column "b" not referenced by COPY
ROLLBACK;
-- should succeed with no effect ("b" remains an empty string, "c" remains NULL)
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NOT_NULL *, FORCE_NULL *);
COMMIT;
SELECT b, c FROM forcetest WHERE a = 4;
b | c
---+------
| NULL
(1 row)
-- should succeed with effect ("b" remains an empty string)
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NOT_NULL *);
COMMIT;
SELECT b, c FROM forcetest WHERE a = 5;
b | c
---+---
|
(1 row)
-- should succeed with effect ("c" remains NULL)
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NULL *);
COMMIT;
SELECT b, c FROM forcetest WHERE a = 6;
b | c
---+------
b | NULL
(1 row)
-- should fail with "conflicting or redundant options" error
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NOT_NULL *, FORCE_NOT_NULL(b));
ERROR: conflicting or redundant options
LINE 1: ...c) FROM STDIN WITH (FORMAT csv, FORCE_NOT_NULL *, FORCE_NOT_...
^
ROLLBACK;
-- should fail with "conflicting or redundant options" error
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NULL *, FORCE_NULL(b));
ERROR: conflicting or redundant options
LINE 1: ... b, c) FROM STDIN WITH (FORMAT csv, FORCE_NULL *, FORCE_NULL...
^
ROLLBACK;
\pset null ''
-- test case with whole-row Var in a check constraint
create table check_con_tbl (f1 int);

30
src/test/regress/sql/copy2.sql
View File

@ -344,6 +344,36 @@ ROLLBACK;
BEGIN;
COPY forcetest (d, e) FROM STDIN WITH (FORMAT csv, FORCE_NULL(b));
ROLLBACK;
-- should succeed with no effect ("b" remains an empty string, "c" remains NULL)
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NOT_NULL *, FORCE_NULL *);
4,,""
\.
COMMIT;
SELECT b, c FROM forcetest WHERE a = 4;
-- should succeed with effect ("b" remains an empty string)
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NOT_NULL *);
5,,""
\.
COMMIT;
SELECT b, c FROM forcetest WHERE a = 5;
-- should succeed with effect ("c" remains NULL)
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NULL *);
6,"b",""
\.
COMMIT;
SELECT b, c FROM forcetest WHERE a = 6;
-- should fail with "conflicting or redundant options" error
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NOT_NULL *, FORCE_NOT_NULL(b));
ROLLBACK;
-- should fail with "conflicting or redundant options" error
BEGIN;
COPY forcetest (a, b, c) FROM STDIN WITH (FORMAT csv, FORCE_NULL *, FORCE_NULL(b));
ROLLBACK;
\pset null ''
-- test case with whole-row Var in a check constraint