Perl6 DBDI YAPC::EU 201008

DBDI for Perl6

In 2007 I said...

Database interfaces for open source languages suck

They’re all limited They’re all different They’re all duplicating development effort

We need a common database driver API for Perl 6 and Parrot

But what?

Mature, Stable, Functional, Object Oriented Well documented, with a test suite Well known to a wide user base Well known to driver developers

JDBC No, not Java, just the JDBC API The class and method names, the semantics the documentation the test suite

Actually, not plain JDBC Sanitize the worst inﬂuences of Java Easier to use for dynamic languages

Your Code DBI v2 API DBI DBDI API DBD Database Client Library

NO JDBC FOR THIS! Your Code DBI v2 API DBI DBDI API DBD USE JDBC Database Client Library FOR THIS

java2perl6api Generates Perl 6 Role modules that mirror the API of speciﬁed Java Classes Originally a GSoC Project by Phil Crow in 2007 http://github.com/timbunce/java2perl6

Recurses into types used Maps Java types to Perl6 $ java2perl6api --add_types jdbclib-typemap --outdir jdbclib java.sql.DriverManager perl6: Rakudo Perl 6, version 2010.07-39-gac8a2ae built on parrot 2.6.0 r48152 loading java.sql.DriverManager loading . java.sql.Connection loading . . java.sql.Array loading . . . java.sql.ResultSet loading . . . . java.io.Reader loading . . . . java.sql.Date loading . . . . java.sql.Ref loading . . . . java.sql.ResultSetMetaData loading . . . . . java.sql.Wrapper loading . . . . java.sql.RowId loading . . . . java.sql.SQLWarning loading . . . . . java.sql.SQLException loading . . . . java.sql.Statement ... wrote jdbclib/java/lang/Enum.pm6 - class java.lang.Enum wrote jdbclib/java/sql/CallableStatement.pm6 - interface java.sql.CallableStatement ... compiling jdbclib/java/sql/SQLException.pm6 - class java.sql.SQLException compiling jdbclib/java/sql/Statement.pm6 - interface java.sql.Statement ... Compiles to .pir for validation and speed

public interface java.sql.Statement extends java.sql.Wrapper { public static final int SUCCESS_NO_INFO; public static final int EXECUTE_FAILED; public abstract boolean execute(java.lang.String) throws java.sql.SQLException; public abstract boolean execute(java.lang.String, int) throws java.sql.SQLException; ... }

role java::sql::Statement does java::sql::Wrapper { method SUCCESS_NO_INFO (--> Int) is export { ... } method EXECUTE_FAILED (--> Int) is export { ... } multi method execute ( Str $v1, --> Bool ) { ... } # throws java.sql.SQLException multi method execute ( Str $v1, Int $v2, --> Bool ) { ... } # throws java.sql.SQLException ... }

MiniDBI (formerly “FakeDBI”) “a tiny subset of DBI in Perl 6” started by Martin Berends “hopefully be obsoleted ASAP” has PostgreSQL and MySQL drivers

DBDI A database driver manager and driver implementation framework in Perl 6 Uses the roles generated by running java2perl6api java.sql.DriverManager http://github.com/timbunce/DBDI

It Runs! A working PostgreSQL driver is included in DBDI It’s very minimal today (August 2010) but it only took a few hours to write

# --- DBDI usage example --- use v6; use DBDI; use DBDI::pglibpq; my $url = @*ARGS.shift || prompt "Enter a 'dbdi:driver:...' URL: "; my $con = DBDI::DriverManager.getConnection($url, 'testuser', 'testpass'); while prompt 'SQL: ' -> $sql { my $result = $con.createStatement.executeQuery($sql); my $meta = $result.getMetaData; my @names = map { $meta.getColumnLabel($_) }, 1..$meta.getColumnCount; say @names.join(", "); while ( $result.next ) { my @row = map { $result.getString($_) }, 1..@names.elems; say @row.join(", "); } }

CURRENT SITUATION Your Code MiniDBI DBDI MiniDBI Drivers DBDI Drivers DB Client Libs BASIC BUT BARE FUNCTIONAL SKELETON

Next steps?

Build up a class/role hirearchy borrowing from open source JDBC drivers Separate driver-speciﬁc logic from driver- independant logic to make it easy to implement drivers Establish infrastructure for logging, exceptions etc.

SOME POINT IN THE FUTURE Your Code MiniDBI Tests MiniDBI Framework DBDI Driver MiniDBI Drivers MiniDBI DBDI Driver DBDI Drivers SUCK BRAINZ FROM MiniDBI TRANSITION DB Client Libs DRIVERS INTO & TEST ENABLER DBDI DRIVERS

SOME POINT IN THE FUTURE Your Code MiniDBI Framework DBDI Driver MiniDBI Drivers DBDI Drivers DB Client Libs Also ADD a DRIVER to access Perl5 DBI using blitzkost

SOME POINT FURTHER IN THE FUTURE Your Code JDBC Test Suite DBI v1/v2/v3/* Sufﬁcient Magic DBDI Framework Driver DBDI Drivers DB Client Libs

Interested? Come and join in! dbdi-dev@perl.org #dbdi on irc.freenode.org

Perl6 DBDI YAPC::EU 201008

by Tim Bunce

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