r3116@asus: jeremy | 2005-11-16 00:17:06 -0800

 Introducing the Firebird adapter.  Closes #1874.


git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3052 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 425 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/firebird_adapter.rb b/activerecord/lib/active_record/connection_adapters/firebird_adapter.rb
new file mode 100644
index 0000000000..6f151131b4
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/firebird_adapter.rb
@@ -0,0 +1,425 @@
+# Author: Ken Kunz <kennethkunz@gmail.com>
+
+require 'active_record/connection_adapters/abstract_adapter'
+
+module FireRuby # :nodoc: all
+  class ResultSet
+    include Enumerable
+  end
+
+  class Database
+    def self.new_from_params(database, host, port, service)
+      db_string = ""
+      if host
+        db_string << host
+        db_string << "/#{service || port}" if service || port
+        db_string << ":"
+      end
+      db_string << database
+      new(db_string)
+    end
+  end
+end
+
+module ActiveRecord
+  class << Base
+    def firebird_connection(config) # :nodoc:
+      require_library_or_gem 'fireruby'
+      config = config.symbolize_keys
+      unless config.has_key?(:database)
+        raise ArgumentError, "No database specified. Missing argument: database."
+      end
+      options = config[:charset] ? { CHARACTER_SET => config[:charset] } : {}
+      db = FireRuby::Database.new_from_params(*config.values_at(:database, :host, :port, :service))
+      connection = db.connect(config[:username], config[:password], options)
+      ConnectionAdapters::FirebirdAdapter.new(connection, logger)
+    end
+  end
+
+  module ConnectionAdapters
+    class FirebirdColumn < Column # :nodoc:
+      VARCHAR_MAX_LENGTH = 32_765
+      BLOB_MAX_LENGTH    = 32_767
+
+      def initialize(name, domain_name, type, sub_type, length, precision, scale, default_source, null_flag)
+        column_type = metadata_to_column_type(type, sub_type)
+        sql_type = domain_name =~ /BOOLEAN/ ? 'BOOLEAN' : column_type
+        super(name.downcase, nil, sql_type, !null_flag)
+        if default_source
+          @default = parse_default(default_source)
+          @cast_type = firebird_cast_type(column_type, length, precision, scale)
+        end
+        @limit = type == 'BLOB' ? BLOB_MAX_LENGTH : length
+      end
+
+      # Submits a _CAST_ query to the database, casting the default value to the specified SQL type.
+      # This enables Firebird to provide an actual value when context variables are used as column
+      # defaults (such as CURRENT_TIMESTAMP).
+      def default
+        if @default
+          sql = "SELECT CAST(#{@default} AS #{@cast_type}) FROM RDB$DATABASE"
+          connection = ActiveRecord::Base.active_connections.values.detect { |conn| conn && conn.adapter_name == 'Firebird' }
+          if connection
+            type_cast connection.execute(sql).to_a.first['CAST']
+          else
+            raise ConnectionNotEstablished, "No Firebird connections established."
+          end
+        end
+      end
+
+      def type_cast(value)
+        if type == :date and value.instance_of?(Time)
+          value.to_date
+        elsif type == :boolean
+          value == true or value == ActiveRecord::ConnectionAdapters::FirebirdAdapter.boolean_domain[:true]
+        else
+          super
+        end
+      end
+
+      private
+        # Maps the internal type returned by Firebird metadata tables to a
+        # SQL type that can be passed to #firebird_cast_type and Column#new
+        def metadata_to_column_type(type, sub_type)
+          case type
+            when 'TEXT'    then 'CHAR'
+            when 'VARYING' then 'VARCHAR'
+            when 'DOUBLE'  then 'DOUBLE PRECISION'
+            when 'BLOB'    then sub_type == 1 ? 'CLOB' : 'BLOB'
+            when 'SHORT', 'LONG', 'INT64'
+              case sub_type
+                when 1 then 'NUMERIC'
+                when 2 then 'DECIMAL'
+                else 'BIGINT'
+              end
+            else type
+          end
+        end
+
+        def parse_default(default_source)
+          default_source =~ /^\s*DEFAULT\s+(.*)\s*$/i
+          return $1 unless $1.upcase == "NULL"
+        end
+
+        # Returns a column definition that can be used in a Firebird CAST statement
+        def firebird_cast_type(column_type, length, precision, scale)
+          case column_type
+            when 'BLOB', 'CLOB'       then "VARCHAR(#{VARCHAR_MAX_LENGTH})"
+            when 'CHAR', 'VARCHAR'    then "#{column_type}(#{length})"
+            when 'NUMERIC', 'DECIMAL' then "#{column_type}(#{precision},#{scale.abs})"
+            else column_type
+          end
+        end
+
+        def simplified_type(field_type)
+          if field_type == 'TIMESTAMP'
+            :datetime
+          else
+            super
+          end
+        end
+    end
+
+    # The Firebird adapter relies on the FireRuby[http://rubyforge.org/projects/fireruby/]
+    # extension, version 0.3.2 or later (available as a gem or from
+    # RubyForge[http://rubyforge.org/projects/fireruby/]). FireRuby works with
+    # Firebird 1.5.x on Linux, OS X and Win32 platforms.
+    #
+    # == Usage Notes
+    #
+    # === Sequence (Generator) Names
+    # The Firebird adapter supports the same approach adopted for the Oracle
+    # adapter. See ActiveRecord::Base#set_sequence_name for more details.
+    #
+    # Note that in general there is no need to create a <tt>BEFORE INSERT</tt>
+    # trigger corresponding to a Firebird sequence generator when using
+    # ActiveRecord. In other words, you don't have to try to make Firebird
+    # simulate an <tt>AUTO_INCREMENT</tt> or +IDENTITY+ column. When saving a
+    # new record, ActiveRecord pre-fetches the next sequence value for the table
+    # and explicitly includes it in the +INSERT+ statement. (Pre-fetching the
+    # next primary key value is the only reliable method for the Firebird
+    # adapter to report back the +id+ after a successful insert.)
+    #
+    # === BOOLEAN Domain
+    # Firebird 1.5 does not provide a native +BOOLEAN+ type. But you can easily
+    # define a +BOOLEAN+ _domain_ for this purpose, e.g.:
+    #
+    #  CREATE DOMAIN D_BOOLEAN AS SMALLINT CHECK (VALUE IN (0, 1));
+    #
+    # When the Firebird adapter encounters a column that is based on a domain
+    # that includes "BOOLEAN" in the domain name, it will attempt to treat
+    # the column as a +BOOLEAN+.
+    #
+    # By default, the Firebird adapter will assume that the BOOLEAN domain is
+    # defined as above.  This can be modified if needed.  For example, if you
+    # have a legacy schema with the following +BOOLEAN+ domain defined:
+    #
+    #  CREATE DOMAIN BOOLEAN AS CHAR(1) CHECK (VALUE IN ('T', 'F'));
+    #
+    # ...you can add the following line to your <tt>environment.rb</tt> file:
+    #
+    #  ActiveRecord::ConnectionAdapters::FirebirdAdapter.boolean_domain = { :true => 'T', :false => 'F' }
+    #
+    # === BLOB Elements
+    # The Firebird adapter currently provides only limited support for +BLOB+
+    # columns. You cannot currently retrieve or insert a +BLOB+ as an IO stream.
+    # When selecting a +BLOB+, the entire element is converted into a String.
+    # When inserting or updating a +BLOB+, the entire value is included in-line
+    # in the SQL statement, limiting you to values <= 32KB in size.
+    #
+    # === Column Name Case Semantics
+    # Firebird and ActiveRecord have somewhat conflicting case semantics for
+    # column names.
+    #
+    # [*Firebird*]
+    #   The standard practice is to use unquoted column names, which can be
+    #   thought of as case-insensitive. (In fact, Firebird converts them to
+    #   uppercase.) Quoted column names (not typically used) are case-sensitive.
+    # [*ActiveRecord*]
+    #   Attribute accessors corresponding to column names are case-sensitive.
+    #   The defaults for primary key and inheritance columns are lowercase, and
+    #   in general, people use lowercase attribute names.
+    #
+    # In order to map between the differing semantics in a way that conforms
+    # to common usage for both Firebird and ActiveRecord, uppercase column names
+    # in Firebird are converted to lowercase attribute names in ActiveRecord,
+    # and vice-versa. Mixed-case column names retain their case in both
+    # directions. Lowercase (quoted) Firebird column names are not supported.
+    # This is similar to the solutions adopted by other adapters.
+    #
+    # In general, the best approach is to use unqouted (case-insensitive) column
+    # names in your Firebird DDL (or if you must quote, use uppercase column
+    # names). These will correspond to lowercase attributes in ActiveRecord.
+    #
+    # For example, a Firebird table based on the following DDL:
+    #
+    #  CREATE TABLE products (
+    #    id BIGINT NOT NULL PRIMARY KEY,
+    #    "TYPE" VARCHAR(50),
+    #    name VARCHAR(255) );
+    #
+    # ...will correspond to an ActiveRecord model class called +Product+ with
+    # the following attributes: +id+, +type+, +name+.
+    #
+    # ==== Quoting <tt>"TYPE"</tt> and other Firebird reserved words:
+    # In ActiveRecord, the default inheritance column name is +type+. The word
+    # _type_ is a Firebird reserved word, so it must be quoted in any Firebird
+    # SQL statements. Because of the case mapping described above, you should
+    # always reference this column using quoted-uppercase syntax
+    # (<tt>"TYPE"</tt>) within Firebird DDL or other SQL statements (as in the
+    # example above). This holds true for any other Firebird reserved words used
+    # as column names as well.
+    #
+    # === Migrations
+    # The Firebird adapter does not currently support Migrations.  I hope to
+    # add this feature in the near future.
+    #
+    # == Connection Options
+    # The following options are supported by the Firebird adapter. None of the
+    # options have default values.
+    #
+    # <tt>:database</tt>::
+    #   <i>Required option.</i> Specifies one of: (i) a Firebird database alias;
+    #   (ii) the full path of a database file; _or_ (iii) a full Firebird
+    #   connection string. <i>Do not specify <tt>:host</tt>, <tt>:service</tt>
+    #   or <tt>:port</tt> as separate options when using a full connection
+    #   string.</i>
+    # <tt>:host</tt>::
+    #   Set to <tt>"remote.host.name"</tt> for remote database connections.
+    #   May be omitted for local connections if a full database path is
+    #   specified for <tt>:database</tt>. Some platforms require a value of
+    #   <tt>"localhost"</tt> for local connections when using a Firebird
+    #   database _alias_.
+    # <tt>:service</tt>::
+    #   Specifies a service name for the connection. Only used if <tt>:host</tt>
+    #   is provided. Required when connecting to a non-standard service.
+    # <tt>:port</tt>::
+    #   Specifies the connection port. Only used if <tt>:host</tt> is provided
+    #   and <tt>:service</tt> is not. Required when connecting to a non-standard
+    #   port and <tt>:service</tt> is not defined.
+    # <tt>:username</tt>::
+    #   Specifies the database user. May be omitted or set to +nil+ (together
+    #   with <tt>:password</tt>) to use the underlying operating system user
+    #   credentials on supported platforms.
+    # <tt>:password</tt>::
+    #   Specifies the database password. Must be provided if <tt>:username</tt>
+    #   is explicitly specified; should be omitted if OS user credentials are
+    #   are being used.
+    # <tt>:charset</tt>::
+    #   Specifies the character set to be used by the connection. Refer to
+    #   Firebird documentation for valid options.
+    class FirebirdAdapter < AbstractAdapter
+      @@boolean_domain = { :true => 1, :false => 0 }
+      cattr_accessor :boolean_domain
+
+      def adapter_name # :nodoc:
+        'Firebird'
+      end
+
+      # Returns true for Firebird adapter (since Firebird requires primary key
+      # values to be pre-fetched before insert). See also #next_sequence_value.
+      def prefetch_primary_key?
+        true
+      end
+
+      def default_sequence_name(table_name, primary_key) # :nodoc:
+        "#{table_name}_seq"
+      end
+
+      # QUOTING ==================================================
+
+      def quote(value, column = nil) # :nodoc:
+        if [Time, DateTime].include?(value.class)
+          "CAST('#{value.strftime("%Y-%m-%d %H:%M:%S")}' AS TIMESTAMP)"
+        else
+          super
+        end
+      end
+
+      def quote_string(string) # :nodoc:
+        string.gsub(/'/, "''")
+      end
+
+      def quote_column_name(column_name) # :nodoc:
+        %Q("#{ar_to_fb_case(column_name)}")
+      end
+
+      def quoted_true # :nodoc:
+        quote(boolean_domain[:true])
+      end
+
+      def quoted_false # :nodoc:
+        quote(boolean_domain[:false])
+      end
+
+      # DATABASE STATEMENTS ======================================
+
+      def select_all(sql, name = nil) # :nodoc:
+        select(sql, name)
+      end
+
+      def select_one(sql, name = nil) # :nodoc:
+        result = select(sql, name)
+        result.nil? ? nil : result.first
+      end
+
+      def execute(sql, name = nil, &block) # :nodoc:
+        log(sql, name) do
+          if @transaction
+            @connection.execute(sql, @transaction, &block)
+          else
+            @connection.execute_immediate(sql, &block)
+          end
+        end
+      end
+
+      def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) # :nodoc:
+        execute(sql, name)
+        id_value
+      end
+
+      alias_method :update, :execute
+      alias_method :delete, :execute
+
+      def begin_db_transaction() # :nodoc:
+        @transaction = @connection.start_transaction
+      end
+
+      def commit_db_transaction() # :nodoc:
+        @transaction.commit
+      ensure
+        @transaction = nil
+      end
+
+      def rollback_db_transaction() # :nodoc:
+        @transaction.rollback
+      ensure
+        @transaction = nil
+      end
+
+      def add_limit_offset!(sql, options) # :nodoc:
+        if options[:limit]
+          limit_string = "FIRST #{options[:limit]}"
+          limit_string << " SKIP #{options[:offset]}" if options[:offset]
+          sql.sub!(/\A(\s*SELECT\s)/i, '\&' + limit_string + ' ')
+        end
+      end
+
+      # Returns the next sequence value from a sequence generator. Not generally
+      # called directly; used by ActiveRecord to get the next primary key value
+      # when inserting a new database record (see #prefetch_primary_key?).
+      def next_sequence_value(sequence_name)
+        FireRuby::Generator.new(sequence_name, @connection).next(1)
+      end
+
+      # SCHEMA STATEMENTS ========================================
+
+      def columns(table_name, name = nil) # :nodoc:
+        sql = <<-END_SQL
+          SELECT r.rdb$field_name, r.rdb$field_source, t.rdb$type_name, f.rdb$field_sub_type,
+                 f.rdb$field_length, f.rdb$field_precision, f.rdb$field_scale,
+                 COALESCE(r.rdb$default_source, f.rdb$default_source) rdb$default_source,
+                 COALESCE(r.rdb$null_flag, f.rdb$null_flag) rdb$null_flag
+          FROM rdb$relation_fields r
+          JOIN rdb$fields f ON r.rdb$field_source = f.rdb$field_name
+          JOIN rdb$types t ON f.rdb$field_type = t.rdb$type
+          WHERE r.rdb$relation_name = '#{table_name.upcase}'
+          AND t.rdb$field_name = 'RDB$FIELD_TYPE'
+          ORDER BY r.rdb$field_position
+        END_SQL
+        execute(sql, name).collect do |field|
+          field_values = field.values.collect do |value|
+            case value
+              when String         then value.rstrip
+              when FireRuby::Blob then value.to_s
+              else value
+            end
+          end
+          FirebirdColumn.new(*field_values)
+        end
+      end
+
+      private
+        def select(sql, name = nil)
+          execute(sql, name).collect do |row|
+            hashed_row = {}
+            # TODO: zip is slow.
+            row.aliases.zip(row.values) do |column_alias, value|
+              value = case value
+                when Time           then guess_date_or_time(value)
+                when FireRuby::Blob then value.to_s
+                else value
+              end
+              hashed_row[fb_to_ar_case(column_alias)] = value
+            end
+            hashed_row
+          end
+        end
+
+        # FireRuby (as of 0.3.2) returns a Time object for TIME, TIMESTAMP and
+        # DATE columns. This method guesses whether time is really a date, and
+        # returns a string representing the date if it is. This date string gets
+        # properly type-cast later (as a Time or Date object) based on the
+        # column type.
+        def guess_date_or_time(time)
+          if (time.hour + time.min + time.sec + time.usec).zero?
+            time.strftime("%Y-%m-%d")
+          else
+            time
+          end
+        end
+
+        # Maps uppercase Firebird column names to lowercase for ActiveRecord;
+        # mixed-case columns retain their original case.
+        def fb_to_ar_case(column_name)
+          column_name =~ /[[:lower:]]/ ? column_name : column_name.downcase
+        end
+
+        # Maps lowercase ActiveRecord column names to uppercase for Fierbird;
+        # mixed-case columns retain their original case.
+        def ar_to_fb_case(column_name)
+          column_name =~ /[[:upper:]]/ ? column_name : column_name.upcase
+        end
+    end
+  end
+end