DB - Base roles for DB::* family of SQL Database Access Modules
This module abstracts out some shared functionality from a set of concrete modules for performing database access.
You can't actually do anything directly with these. The documentation here will only be useful if you want to understand the internals of the DB modules, or implement your own similar DB::* module.
DB holds a cache of database connections.
.connect(--> DB::Connection) - virtual, create a new connection
.db(--> DB::Connection) - Returns a cached connection
.cache(DB::Connection:D $db) - Returns a connection to the cache
.query() - Allocates a connection, calls
.query, then returns
.execute() - Allocates a connection, calls
returns the connection.
.finish() - For each cached connection, call
A single active database connection. It also implements functionality for a statement cache per connection, so you don't have to remember which statement was prepared, just call it again.
.ping(--> Bool) - test if a connection is still active/viable, to be
overridden if possible.
.free() - free the connection, don't make a
DESTROY(), make this
instead, to be overridden.
.clear-cache() - Call
.DESTROY() for each cached
.finish() - Return connection to the main object's cache.
.prepare-nocache(Str:D $query --> DB::Statement) - virtual, prepare
the query as a statement.
.prepare(Str:D $query --> DB::Statement) - Return a cached
statement, or call
.execute(Str:D $command, Bool :$finish, |args) - virtual method to
execute a command. The
$finish argument says to call
execute is finished.
.query(Str:D $query, Bool :$finish, |args) - prepare, then execute
.rollback - shortcuts
A prepared statement, ready to execute.
.free() - Free all resources
.execute() - virtual method
.finish() - Call the
.finish on the owning Connection
.DESTROY() - Just call
This gets returned with results of a query. It holds the
and relays the finish back up to the
Statement to the
.free() - Free any resources, to be overridden if needed
.finish() - call
.free, then call
.finish on the
that returned these results.
.row() - virtual, return the next row of results
.names() - virtual, return the string labels for the columns in the
results, used to construct
.keys() - Cache for
.names so we only call it once.
.hashes - Return results,
.DESTROY() - just call
Inspiration taken from the existing Perl6 DBIish module as well as the Perl 5 Mojo::Pg from the Mojolicious project.