This document introduces Hideaki Ohno and his work with foreign data wrappers. It discusses using foreign data wrappers with PostgreSQL to access data from other systems like MySQL, Twitter, and IMAP. It also describes the Perl foreign data wrapper module he created called perl_fdw that allows querying external Perl modules from PostgreSQL using foreign tables.

1. Hachioji.pm #11
2011/12/3

2. About Me
Hideaki Ohno
Twitter : @hide_o_55
Hatena: id:hide_o_55
github: http://hideo55.github.com/

3. Theme

4. Theme

5. DB

7. DB

8. MySQL

9. PostgreSQL

10. PostgreSQL
Foreign Data Wrapper
Perl

11. Foreign Data Wrapper
SQL MED(Management of External
Data) PostgreSQL
PostgreSQL
PostgreSQL 9.1
MySQL, Twitter, IMAP ...

12. Foreign Data Wrapper
typedef FdwPlan *(*PlanForeignScan_function) (Oid foreigntableid,
PlannerInfo
*root,
RelOptInfo
*baserel);
typedef void (*ExplainForeignScan_function) (ForeignScanState *node,
struct ExplainState
*es);
typedef void (*BeginForeignScan_function) (ForeignScanState *node,
int eflags);
typedef TupleTableSlot *(*IterateForeignScan_function) (ForeignScanState
*node);
typedef void (*ReScanForeignScan_function) (ForeignScanState *node);
typedef void (*EndForeignScan_function) (ForeignScanState *node);
typedef struct FdwRoutine
{
NodeTag type;
PlanForeignScan_function PlanForeignScan;
ExplainForeignScan_function ExplainForeignScan;
BeginForeignScan_function BeginForeignScan;
IterateForeignScan_function IterateForeignScan;
ReScanForeignScan_function ReScanForeignScan;
EndForeignScan_function EndForeignScan;
} FdwRoutine;

13. perl_fdw
Datum perl_fdw_handler( PG_FUNCTION_ARGS) {
FdwRoutine *fdwroutine = makeNode(FdwRoutine);
fdwroutine->PlanForeignScan = perlPlanForeignScan;
fdwroutine->ExplainForeignScan = perlExplainForeignScan;
fdwroutine->BeginForeignScan = perlBeginForeignScan;
fdwroutine->IterateForeignScan = perlIterateForeignScan;
fdwroutine->ReScanForeignScan = perlReScanForeignScan;
fdwroutine->EndForeignScan = perlEndForeignScan;
PG_RETURN_POINTER(fdwroutine);
}

14. perl_fdw

15. perl_fdw
CREATE EXTENSION perl_fdw;
CREATE SERVER perl_hoge FOREIGN
DATA WRAPPER perl_fdw
options (
wrapper 'Foo::Bar'
);

16. perl_fdw
CREATE FOREIGN TABLE hoge (
id INTEGER,
name text
) SERVER perl_hoge OPTIONS(
foo ‘bar’
);

17. m(__)m

18. PGXN(PostgreSQL Extension Network)
Chrome Extension PGXN Search
https://github.com/hideo55/chrome-pgxn-search