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Attached is an update to contrib/tablefunc. It introduces a new

Browse source 
function, connectby(), which can serve as a reference implementation for

the changes made in the last few days -- namely the ability of a
function to return an entire tuplestore, and the ability of a function
to make use of the query provided "expected" tuple description.

Description:

   connectby(text relname, text keyid_fld, text parent_keyid_fld,
     text start_with, int max_depth [, text branch_delim])
   - returns keyid, parent_keyid, level, and an optional branch string
   - requires anonymous composite type syntax in the FROM clause. See
     the instructions in the documentation below.

Joe Conway
This commit is contained in:
Bruce Momjian 2002-09-02 05:44:05 +00:00
parent 9fd842c4b2
commit 6aa4482f2f
5 changed files with 602 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

109
contrib/tablefunc/README.tablefunc
View file

@ -60,6 +60,12 @@ Installation:
- requires anonymous composite type syntax in the FROM clause. See
the instructions in the documentation below.
connectby(text relname, text keyid_fld, text parent_keyid_fld,
text start_with, int max_depth [, text branch_delim])
- returns keyid, parent_keyid, level, and an optional branch string
- requires anonymous composite type syntax in the FROM clause. See
the instructions in the documentation below.
Documentation
==================================================================
Name
@ -324,6 +330,109 @@ AS ct(row_name text, category_1 text, category_2 text, category_3 text);
test2 | val6 | val7 |
(2 rows)
==================================================================
Name
connectby(text, text, text, text, int[, text]) - returns a set
representing a hierarchy (tree structure)
Synopsis
connectby(text relname, text keyid_fld, text parent_keyid_fld,
text start_with, int max_depth [, text branch_delim])
Inputs
relname
Name of the source relation
keyid_fld
Name of the key field
parent_keyid_fld
Name of the key_parent field
start_with
root value of the tree input as a text value regardless of keyid_fld type
max_depth
zero (0) for unlimited depth, otherwise restrict level to this depth
branch_delim
if optional branch value is desired, this string is used as the delimiter
Outputs
Returns setof record, which must defined with a column definition
in the FROM clause of the SELECT statement, e.g.:
SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0, '~')
AS t(keyid text, parent_keyid text, level int, branch text);
- or -
SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0)
AS t(keyid text, parent_keyid text, level int);
Notes
1. keyid and parent_keyid must be the same data type
2. The column definition *must* include a third column of type INT4 for
the level value output
3. If the branch field is not desired, omit both the branch_delim input
parameter *and* the branch field in the query column definition
4. If the branch field is desired, it must be the forth column in the query
column definition, and it must be type TEXT
Example usage
CREATE TABLE connectby_tree(keyid text, parent_keyid text);
INSERT INTO connectby_tree VALUES('row1',NULL);
INSERT INTO connectby_tree VALUES('row2','row1');
INSERT INTO connectby_tree VALUES('row3','row1');
INSERT INTO connectby_tree VALUES('row4','row2');
INSERT INTO connectby_tree VALUES('row5','row2');
INSERT INTO connectby_tree VALUES('row6','row4');
INSERT INTO connectby_tree VALUES('row7','row3');
INSERT INTO connectby_tree VALUES('row8','row6');
INSERT INTO connectby_tree VALUES('row9','row5');
-- with branch
SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0, '~')
AS t(keyid text, parent_keyid text, level int, branch text);
keyid | parent_keyid | level | branch
-------+--------------+-------+---------------------
row2 | | 0 | row2
row4 | row2 | 1 | row2~row4
row6 | row4 | 2 | row2~row4~row6
row8 | row6 | 3 | row2~row4~row6~row8
row5 | row2 | 1 | row2~row5
row9 | row5 | 2 | row2~row5~row9
(6 rows)
-- without branch
SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0)
AS t(keyid text, parent_keyid text, level int);
keyid | parent_keyid | level
-------+--------------+-------
row2 | | 0
row4 | row2 | 1
row6 | row4 | 2
row8 | row6 | 3
row5 | row2 | 1
row9 | row5 | 2
(6 rows)
==================================================================
-- Joe Conway

46
contrib/tablefunc/tablefunc-test.sql
View file

@ -1,8 +1,3 @@
--
-- show_all_settings()
--
SELECT * FROM show_all_settings();
--
-- normal_rand()
--
@ -47,3 +42,44 @@ select * from crosstab4('select rowid, attribute, value from ct where rowclass =
select * from crosstab('select rowid, attribute, value from ct where rowclass = ''group1'' order by 1,2;', 2) as c(rowid text, att1 text, att2 text);
select * from crosstab('select rowid, attribute, value from ct where rowclass = ''group1'' order by 1,2;', 3) as c(rowid text, att1 text, att2 text, att3 text);
select * from crosstab('select rowid, attribute, value from ct where rowclass = ''group1'' order by 1,2;', 4) as c(rowid text, att1 text, att2 text, att3 text, att4 text);
-- test connectby with text based hierarchy
DROP TABLE connectby_tree;
CREATE TABLE connectby_tree(keyid text, parent_keyid text);
INSERT INTO connectby_tree VALUES('row1',NULL);
INSERT INTO connectby_tree VALUES('row2','row1');
INSERT INTO connectby_tree VALUES('row3','row1');
INSERT INTO connectby_tree VALUES('row4','row2');
INSERT INTO connectby_tree VALUES('row5','row2');
INSERT INTO connectby_tree VALUES('row6','row4');
INSERT INTO connectby_tree VALUES('row7','row3');
INSERT INTO connectby_tree VALUES('row8','row6');
INSERT INTO connectby_tree VALUES('row9','row5');
-- with branch
SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0, '~') AS t(keyid text, parent_keyid text, level int, branch text);
-- without branch
SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', 'row2', 0) AS t(keyid text, parent_keyid text, level int);
-- test connectby with int based hierarchy
DROP TABLE connectby_tree;
CREATE TABLE connectby_tree(keyid int, parent_keyid int);
INSERT INTO connectby_tree VALUES(1,NULL);
INSERT INTO connectby_tree VALUES(2,1);
INSERT INTO connectby_tree VALUES(3,1);
INSERT INTO connectby_tree VALUES(4,2);
INSERT INTO connectby_tree VALUES(5,2);
INSERT INTO connectby_tree VALUES(6,4);
INSERT INTO connectby_tree VALUES(7,3);
INSERT INTO connectby_tree VALUES(8,6);
INSERT INTO connectby_tree VALUES(9,5);
-- with branch
SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', '2', 0, '~') AS t(keyid int, parent_keyid int, level int, branch text);
-- without branch
SELECT * FROM connectby('connectby_tree', 'keyid', 'parent_keyid', '2', 0) AS t(keyid int, parent_keyid int, level int);

448
contrib/tablefunc/tablefunc.c
View file

@ -32,16 +32,42 @@
#include "fmgr.h"
#include "funcapi.h"
#include "executor/spi.h"
#include "executor/spi.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "tablefunc.h"
static bool compatTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2);
static void validateConnectbyTupleDesc(TupleDesc tupdesc, bool show_branch);
static bool compatCrosstabTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2);
static bool compatConnectbyTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2);
static void get_normal_pair(float8 *x1, float8 *x2);
static TupleDesc make_crosstab_tupledesc(TupleDesc spi_tupdesc, int num_catagories);
static TupleDesc make_crosstab_tupledesc(TupleDesc spi_tupdesc,
int num_catagories);
static Tuplestorestate *connectby(char *relname,
char *key_fld,
char *parent_key_fld,
char *branch_delim,
char *start_with,
int max_depth,
bool show_branch,
MemoryContext per_query_ctx,
AttInMetadata *attinmeta);
static Tuplestorestate *build_tuplestore_recursively(char *key_fld,
char *parent_key_fld,
char *relname,
char *branch_delim,
char *start_with,
char *branch,
int level,
int max_depth,
bool show_branch,
MemoryContext per_query_ctx,
AttInMetadata *attinmeta,
Tuplestorestate *tupstore);
static char *quote_ident_cstr(char *rawstr);
typedef struct
{
@ -68,6 +94,9 @@ typedef struct
} \
} while (0)
/* sign, 10 digits, '\0' */
#define INT32_STRLEN 12
/*
* normal_rand - return requested number of random values
* with a Gaussian (Normal) distribution.
@ -358,7 +387,7 @@ crosstab(PG_FUNCTION_ARGS)
* from ret_relname, at least based on number and type of
* attributes
*/
if (!compatTupleDescs(tupdesc, spi_tupdesc))
if (!compatCrosstabTupleDescs(tupdesc, spi_tupdesc))
elog(ERROR, "crosstab: return and sql tuple descriptions are"
" incompatible");
@ -558,11 +587,401 @@ crosstab(PG_FUNCTION_ARGS)
}
}
/*
* connectby_text - produce a result set from a hierarchical (parent/child)
* table.
*
* e.g. given table foo:
*
* keyid parent_keyid
* ------+--------------
* row1 NULL
* row2 row1
* row3 row1
* row4 row2
* row5 row2
* row6 row4
* row7 row3
* row8 row6
* row9 row5
*
*
* connectby(text relname, text keyid_fld, text parent_keyid_fld,
* text start_with, int max_depth [, text branch_delim])
* connectby('foo', 'keyid', 'parent_keyid', 'row2', 0, '~') returns:
*
* keyid parent_id level branch
* ------+-----------+--------+-----------------------
* row2 NULL 0 row2
* row4 row2 1 row2~row4
* row6 row4 2 row2~row4~row6
* row8 row6 3 row2~row4~row6~row8
* row5 row2 1 row2~row5
* row9 row5 2 row2~row5~row9
*
*/
PG_FUNCTION_INFO_V1(connectby_text);
#define CONNECTBY_NCOLS 4
#define CONNECTBY_NCOLS_NOBRANCH 3
Datum
connectby_text(PG_FUNCTION_ARGS)
{
char *relname = GET_STR(PG_GETARG_TEXT_P(0));
char *key_fld = GET_STR(PG_GETARG_TEXT_P(1));
char *parent_key_fld = GET_STR(PG_GETARG_TEXT_P(2));
char *start_with = GET_STR(PG_GETARG_TEXT_P(3));
int max_depth = PG_GETARG_INT32(4);
char *branch_delim = NULL;
bool show_branch = false;
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
AttInMetadata *attinmeta;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
if (fcinfo->nargs == 6)
{
branch_delim = GET_STR(PG_GETARG_TEXT_P(5));
show_branch = true;
}
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/* get the requested return tuple description */
tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
/* does it meet our needs */
validateConnectbyTupleDesc(tupdesc, show_branch);
/* OK, use it then */
attinmeta = TupleDescGetAttInMetadata(tupdesc);
/* check to see if caller supports us returning a tuplestore */
if (!rsinfo->allowedModes & SFRM_Materialize)
elog(ERROR, "connectby requires Materialize mode, but it is not "
"allowed in this context");
/* OK, go to work */
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = connectby(relname,
key_fld,
parent_key_fld,
branch_delim,
start_with,
max_depth,
show_branch,
per_query_ctx,
attinmeta);
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
/*
* SFRM_Materialize mode expects us to return a NULL Datum.
* The actual tuples are in our tuplestore and passed back through
* rsinfo->setResult. rsinfo->setDesc is set to the tuple description
* that we actually used to build our tuples with, so the caller can
* verify we did what it was expecting.
*/
return (Datum) 0;
}
/*
* connectby - does the real work for connectby_text()
*/
static Tuplestorestate *
connectby(char *relname,
char *key_fld,
char *parent_key_fld,
char *branch_delim,
char *start_with,
int max_depth,
bool show_branch,
MemoryContext per_query_ctx,
AttInMetadata *attinmeta)
{
Tuplestorestate *tupstore = NULL;
int ret;
MemoryContext oldcontext;
/* Connect to SPI manager */
if ((ret = SPI_connect()) < 0)
elog(ERROR, "connectby: SPI_connect returned %d", ret);
/* switch to longer term context to create the tuple store */
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/* initialize our tuplestore */
tupstore = tuplestore_begin_heap(true, SortMem);
MemoryContextSwitchTo(oldcontext);
/* now go get the whole tree */
tupstore = build_tuplestore_recursively(key_fld,
parent_key_fld,
relname,
branch_delim,
start_with,
start_with, /* current_branch */
0, /* initial level is 0 */
max_depth,
show_branch,
per_query_ctx,
attinmeta,
tupstore);
SPI_finish();
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tuplestore_donestoring(tupstore);
MemoryContextSwitchTo(oldcontext);
return tupstore;
}
static Tuplestorestate *
build_tuplestore_recursively(char *key_fld,
char *parent_key_fld,
char *relname,
char *branch_delim,
char *start_with,
char *branch,
int level,
int max_depth,
bool show_branch,
MemoryContext per_query_ctx,
AttInMetadata *attinmeta,
Tuplestorestate *tupstore)
{
TupleDesc tupdesc = attinmeta->tupdesc;
MemoryContext oldcontext;
StringInfo sql = makeStringInfo();
int ret;
int proc;
if(max_depth > 0 && level > max_depth)
return tupstore;
/* Build initial sql statement */
appendStringInfo(sql, "SELECT %s, %s FROM %s WHERE %s = '%s' AND %s IS NOT NULL",
quote_ident_cstr(key_fld),
quote_ident_cstr(parent_key_fld),
quote_ident_cstr(relname),
quote_ident_cstr(parent_key_fld),
start_with,
quote_ident_cstr(key_fld));
/* Retrieve the desired rows */
ret = SPI_exec(sql->data, 0);
proc = SPI_processed;
/* Check for qualifying tuples */
if ((ret == SPI_OK_SELECT) && (proc > 0))
{
HeapTuple tuple;
HeapTuple spi_tuple;
SPITupleTable *tuptable = SPI_tuptable;
TupleDesc spi_tupdesc = tuptable->tupdesc;
int i;
char *current_key;
char *current_key_parent;
char current_level[INT32_STRLEN];
char *current_branch;
char **values;
if (show_branch)
values = (char **) palloc(CONNECTBY_NCOLS * sizeof(char *));
else
values = (char **) palloc(CONNECTBY_NCOLS_NOBRANCH * sizeof(char *));
/* First time through, do a little setup */
if (level == 0)
{
/*
* Check that return tupdesc is compatible with the one we got
* from the query, but only at level 0 -- no need to check more
* than once
*/
if (!compatConnectbyTupleDescs(tupdesc, spi_tupdesc))
elog(ERROR, "connectby: return and sql tuple descriptions are "
"incompatible");
/* root value is the one we initially start with */
values[0] = start_with;
/* root value has no parent */
values[1] = NULL;
/* root level is 0 */
sprintf(current_level, "%d", level);
values[2] = current_level;
/* root branch is just starting root value */
if (show_branch)
values[3] = start_with;
/* construct the tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* switch to long lived context while storing the tuple */
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/* now store it */
tuplestore_puttuple(tupstore, tuple);
/* now reset the context */
MemoryContextSwitchTo(oldcontext);
/* increment level */
level++;
}
for (i = 0; i < proc; i++)
{
StringInfo branchstr = NULL;
/* start a new branch */
if (show_branch)
{
branchstr = makeStringInfo();
appendStringInfo(branchstr, "%s", branch);
}
/* get the next sql result tuple */
spi_tuple = tuptable->vals[i];
/* get the current key and parent */
current_key = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
current_key_parent = pstrdup(SPI_getvalue(spi_tuple, spi_tupdesc, 2));
/* get the current level */
sprintf(current_level, "%d", level);
/* extend the branch */
if (show_branch)
{
appendStringInfo(branchstr, "%s%s", branch_delim, current_key);
current_branch = branchstr->data;
}
else
current_branch = NULL;
/* build a tuple */
values[0] = pstrdup(current_key);
values[1] = current_key_parent;
values[2] = current_level;
if (show_branch)
values[3] = current_branch;
tuple = BuildTupleFromCStrings(attinmeta, values);
xpfree(current_key);
xpfree(current_key_parent);
/* switch to long lived context while storing the tuple */
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/* store the tuple for later use */
tuplestore_puttuple(tupstore, tuple);
/* now reset the context */
MemoryContextSwitchTo(oldcontext);
heap_freetuple(tuple);
/* recurse using current_key_parent as the new start_with */
tupstore = build_tuplestore_recursively(key_fld,
parent_key_fld,
relname,
branch_delim,
values[0],
current_branch,
level + 1,
max_depth,
show_branch,
per_query_ctx,
attinmeta,
tupstore);
}
}
return tupstore;
}
/*
* Check expected (query runtime) tupdesc suitable for Connectby
*/
static void
validateConnectbyTupleDesc(TupleDesc tupdesc, bool show_branch)
{
/* are there the correct number of columns */
if (show_branch)
{
if (tupdesc->natts != CONNECTBY_NCOLS)
elog(ERROR, "Query-specified return tuple not valid for Connectby: "
"wrong number of columns");
}
else
{
if (tupdesc->natts != CONNECTBY_NCOLS_NOBRANCH)
elog(ERROR, "Query-specified return tuple not valid for Connectby: "
"wrong number of columns");
}
/* check that the types of the first two columns match */
if (tupdesc->attrs[0]->atttypid != tupdesc->attrs[1]->atttypid)
elog(ERROR, "Query-specified return tuple not valid for Connectby: "
"first two columns must be the same type");
/* check that the type of the third column is INT4 */
if (tupdesc->attrs[2]->atttypid != INT4OID)
elog(ERROR, "Query-specified return tuple not valid for Connectby: "
"third column must be type %s", format_type_be(INT4OID));
/* check that the type of the forth column is TEXT if applicable */
if (show_branch && tupdesc->attrs[3]->atttypid != TEXTOID)
elog(ERROR, "Query-specified return tuple not valid for Connectby: "
"third column must be type %s", format_type_be(TEXTOID));
/* OK, the tupdesc is valid for our purposes */
}
/*
* Check if spi sql tupdesc and return tupdesc are compatible
*/
static bool
compatConnectbyTupleDescs(TupleDesc ret_tupdesc, TupleDesc sql_tupdesc)
{
Oid ret_atttypid;
Oid sql_atttypid;
/* check the key_fld types match */
ret_atttypid = ret_tupdesc->attrs[0]->atttypid;
sql_atttypid = sql_tupdesc->attrs[0]->atttypid;
if (ret_atttypid != sql_atttypid)
elog(ERROR, "compatConnectbyTupleDescs: SQL key field datatype does "
"not match return key field datatype");
/* check the parent_key_fld types match */
ret_atttypid = ret_tupdesc->attrs[1]->atttypid;
sql_atttypid = sql_tupdesc->attrs[1]->atttypid;
if (ret_atttypid != sql_atttypid)
elog(ERROR, "compatConnectbyTupleDescs: SQL parent key field datatype "
"does not match return parent key field datatype");
/* OK, the two tupdescs are compatible for our purposes */
return true;
}
/*
* Check if two tupdescs match in type of attributes
*/
static bool
compatTupleDescs(TupleDesc ret_tupdesc, TupleDesc sql_tupdesc)
compatCrosstabTupleDescs(TupleDesc ret_tupdesc, TupleDesc sql_tupdesc)
{
int i;
Form_pg_attribute ret_attr;
@ -574,7 +993,7 @@ compatTupleDescs(TupleDesc ret_tupdesc, TupleDesc sql_tupdesc)
ret_atttypid = ret_tupdesc->attrs[0]->atttypid;
sql_atttypid = sql_tupdesc->attrs[0]->atttypid;
if (ret_atttypid != sql_atttypid)
elog(ERROR, "compatTupleDescs: SQL rowid datatype does not match"
elog(ERROR, "compatCrosstabTupleDescs: SQL rowid datatype does not match"
" return rowid datatype");
/*
@ -643,3 +1062,20 @@ make_crosstab_tupledesc(TupleDesc spi_tupdesc, int num_catagories)
return tupdesc;
}
/*
* Return a properly quoted identifier.
* Uses quote_ident in quote.c
*/
static char *
quote_ident_cstr(char *rawstr)
{
text *rawstr_text;
text *result_text;
char *result;
rawstr_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(rawstr)));
result_text = DatumGetTextP(DirectFunctionCall1(quote_ident, PointerGetDatum(rawstr_text)));
result = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(result_text)));
return result;
}

1
contrib/tablefunc/tablefunc.h
View file

@ -34,5 +34,6 @@
*/
extern Datum normal_rand(PG_FUNCTION_ARGS);
extern Datum crosstab(PG_FUNCTION_ARGS);
extern Datum connectby_text(PG_FUNCTION_ARGS);
#endif /* TABLEFUNC_H */

10
contrib/tablefunc/tablefunc.sql.in
View file

@ -37,4 +37,12 @@ CREATE OR REPLACE FUNCTION crosstab4(text)
CREATE OR REPLACE FUNCTION crosstab(text,int)
RETURNS setof record
AS 'MODULE_PATHNAME','crosstab' LANGUAGE 'c' STABLE STRICT;
AS 'MODULE_PATHNAME','crosstab' LANGUAGE 'c' STABLE STRICT;
CREATE OR REPLACE FUNCTION connectby(text,text,text,text,int,text)
RETURNS setof record
AS 'MODULE_PATHNAME','connectby_text' LANGUAGE 'c' STABLE STRICT;
CREATE OR REPLACE FUNCTION connectby(text,text,text,text,int)
RETURNS setof record
AS 'MODULE_PATHNAME','connectby_text' LANGUAGE 'c' STABLE STRICT;