sub reverse_engineer { my $self = shift; my $schema = shift;
my $dbh = $schema->driver->handle; foreach my $table ( $dbh->tables ) { my $t = $schema->make_table( name => $table ); $self->reverse_engineer_table($t); } }
sub reverse_engineer_table { my $self = shift; my $table = shift;
my $dbh = $table->schema->driver->handle; my $sth = $dbh->column_info( undef, $table->schema->name, $table->name, undef ); while ( my $col_info = $sth->fetchrow_hashref ) { use Data::Dumper; warn Dumper $col_info; my %attr = ( name => $col_info->{COLUMN_NAME}, type => $col_info->{TYPE_NAME}, nullable => $col_info->{NULLABLE} ? 1 : 0, ); $attr{size} = $col_info->{COLUMN_SIZE} if $col_info->{COLUMN_SIZE}; $attr{precision} = $col_info->{DECIMAL_DIGITS} if $col_info->{DECIMAL_DIGITS}; $attr{default} = $col_info->{COLUMN_DEF} if defined $col_info->{COLUMN_DEF}; $attr{comment} = $col_info->{REMARKS} if defined $col_info->{REMARKS}; $table->make_column(%attr); } $self->reverse_engineer_table_primary_key($table); }
sub reverse_engineer_table_primary_key { my $self = shift; my $table = shift;
my $dbh = $table->schema->driver->handle; my $sth = $dbh->column_info( undef, $table->schema->name, $table->name ); while ( my $pk_info = $sth->fetchrow_hashref ) { $table->add_primary_key( $table->column( $pk_info->{COLUMN_NAME} ) ); } }
Alzabo::RDBMSRules - Base class for Alzabo RDBMS rulesets
use Alzabo::RDBMSRules; my $rules = Alzabo::RDBMSRules( rules => 'MySQL' );
This class is the base class for all Alzabo::RDBMSRules modules. To instantiate a subclass call this class's new() method. See the "SUBCLASSING Alzabo::RDBMSRules" section for information on how to make a ruleset for the RDBMS of your choice.
Alzabo::RDBMSRules
new()
A list of names representing the available Alzabo::RDBMSRules subclasses. Any one of these names would be appropriate as the "rdbms" parameter for the Alzabo::RDBMSRules->new() method.
Alzabo::RDBMSRules->new()
The constructor always accepts one parameter, "rdbms", which is the name of the RDBMS to be used.
Some subclasses may accept additional values.
The constructor returns a new Alzabo::RDBMSRules object of the appropriate subclass.
Throws: Alzabo::Exception::Eval
Alzabo::Exception::Eval
Alzabo::Create::Schema
Returns a list of SQL statements which would create the given schema.
Alzabo::Create::Index
Returns a list of SQL statements to create the specified index.
Alzabo::Create::Table
Returns a list of SQL statements to drop the specified table.
Returns a list of SQL statements to drop the specified index.
This method takes two parameters:
new => Alzabo::Create::Schema object
old => Alzabo::Create::Schema object
This method compares the two schema objects and returns an array of SQL statements which turn the "old" schema into the "new" one.
new => Alzabo::Create::Table object
old => Alzabo::Create::Table object
This method compares the two table objects and returns an array of SQL statements which turn the "old" table into the "new" one.
Alzabo::Column
Returns a boolean indicating whether or not the column is numeric (integer or floating point).
Returns true or false to indicate whether or not the generated DDL SQL statements should have their identifiers quoted or not. This may be overridden by subclasses. It defaults to false.
If this is true, then when syncing a schema, the object will call alter_table_name_sql() to change the table's name. Otherwise it will call recreate_table_sql().
alter_table_name_sql()
recreate_table_sql()
If this is true, then when syncing a schema, the object will call alter_column_name_sql() to change the table's name. Otherwise it will call recreate_table_sql().
alter_column_name_sql()
The following methods are not implemented in the Alzabo::RDBMSRules class itself and must be implemented in its subclasses.
Returns a list of valid column types.
Given a string defining a feature, this method indicates whether or not the given RDBMS supports that feature. By default, this method always returns false unless overridden in the subclass.
Features that may be asked for:
extended_column_types
Column types that must be input directly from a user, as opposed to being chosen from a list. MySQL's ENUM and SET types are examples of such types.
index_column_prefixes
MySQL supports the notion of column prefixes in indexes, allowing you to index only a portion of a large text column.
fulltext_indexes
This should be self-explanatory.
functional_indexes
Indexes on functions, as supported by PostgreSQL.
Alzabo::Schema
Throws an Alzabo::Exception::RDBMSRules if the schema's name is not valid.
Alzabo::Exception::RDBMSRules
Throws an Alzabo::Exception::RDBMSRules if the table's name is not valid.
Alzabo::Create::Column
Throws an Alzabo::Exception::RDBMSRules if the column's name is not valid.
Throws an Alzabo::Exception::RDBMSRules if the type is not valid.
This method returns a canonized version of the type.
Throws an Alzabo::Exception::RDBMSRules if the length or precision is not valid for the given column.
column => Alzabo::Create::Column object
attribute => $attribute
This method is a bit different from the others in that it takes an existing column object and a potential attribute.
It throws an Alzabo::Exception::RDBMSRules if the attribute is is not valid for the column.
Throws an Alzabo::Exception::RDBMSRules if the column is not a valid primary key for its table.
Throws an Alzabo::Exception::RDBMSRules if the column cannot be sequenced.
Throws an Alzabo::Exception::RDBMSRules if the index is not valid.
Returns an array of SQL statements to create the specified table.
Returns an array of SQL statements to create the specified column.
Alzabo::Create::ForeignKey
Returns an array of SQL statements to create the specified foreign key.
Returns an array of SQL statements to drop the specified column.
Returns an array of SQL statements to drop the specified foreign key.
Returns an array of SQL statements to add the specified column.
new => Alzabo::Create::Column object
old => Alzabo::Create::Column object
new => Alzabo::Create::Index object
old => Alzabo::Create::Index object
This method compares the two index objects and returns an array of SQL statements which turn the "old" index into the "new" one.
This method compares the two table objects and returns an array of SQL statements which alter the "old" one's primary key to match the "new" one's.
Given a table, this method is expected to change the table's name from $table->former_name to $table->name. This will only be called if the rules object returns true for can_alter_table_name().
$table->former_name
$table->name
can_alter_table_name()
Given a column, this method is expected to change the table's name from $column->former_name to $column->name. This will only be called if the rules object returns true for can_alter_column_name().
$column->former_name
$column->name
can_alter_column_name()
This method is expected to drop the old table and create the new one.
However, it must preserve all the data stored in the old table, excluding data in columns that are being dropped. Additionally, if there are sequences associated with columns in the old table, they should not be dropped.
This method will only be called if either can_alter_table_name() or can_alter_column_name() return false.
Given a schema object (which presumably has no tables), this method uses the schema's Alzabo::Driver object to connect to an existing database and reverse engineer it into the appropriate Alzabo objects.
Alzabo::Driver
Returns a boolean indicating whether or not the column is an integer type.
Returns a boolean indicating whether or not the column is a floating point type.
Returns a boolean indicating whether or not the column is a character type. This is defined as any type which is defined to store text, regardless of length.
Returns a boolean indicating whether or not the column is a date type. This is not true for datetime types.
Returns a boolean indicating whether or not the column is a datetime type. This is not true for date types.
Returns a boolean indicating whether or not the column is a time type. This is not true for datetime types.
Returns a boolean indicating whether or not the column is a time interval type.
To create a subclass of Alzabo::RDBMSRules for your particular RDBMS is fairly simple.
Here's a sample header to the module using a fictional RDBMS called FooDB:
package Alzabo::RDBMSRules::FooDB; use strict; use vars qw($VERSION); use Alzabo::RDBMSRules; use base qw(Alzabo::RDBMSRules);
The next step is to implement a new() method and the methods listed under the section "Virtual Methods". The new method should look a bit like this:
1: sub new 2: { 3: my $proto = shift; 4: my $class = ref $proto || $proto; 5: my %p = @_; 6: 7: my $self = bless {}, $self; 8: 9: return $self; 10: }
The hash %p contains any values passed to the Alzabo::RDBMSRules->new method by its caller.
Alzabo::RDBMSRules->new
Lines 1-7 should probably be copied verbatim into your own new method. Line 5 can be deleted if you don't need to look at the parameters.
new
The rest of your module should simply implement the methods listed under the "Virtual Methods" section of this documentation.
Look at the included Alzabo::RDBMSRules subclasses for examples. Feel free to contact me for further help if you get stuck. Please tell me what database you're attempting to implement, and include the code you've written so far.
Dave Rolsky, <dave@urth.org>
To install Alzabo, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Alzabo
CPAN shell
perl -MCPAN -e shell install Alzabo
For more information on module installation, please visit the detailed CPAN module installation guide.