Class: Janko::Connection

Inherits:
Object
  • Object
show all
Includes:
Agrippa::Delegation
Defined in:
lib/janko/connection.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(backend) ⇒ Connection

Returns a new instance of Connection.



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# File 'lib/janko/connection.rb', line 36

def initialize(backend)
    @backend = extract_raw_connection(backend)
end

Instance Attribute Details

#backend ⇒ Object (readonly)

Returns the value of attribute backend.



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# File 'lib/janko/connection.rb', line 31

def backend
  @backend
end

Class Method Details

.build(backend) ⇒ Object 



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# File 'lib/janko/connection.rb', line 8

def Connection.build(backend)
    return(default) if backend.nil?
    return(backend) if backend.is_a?(Connection)
    new(backend)
end

.cache_catalog ⇒ Object 



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# File 'lib/janko/connection.rb', line 22

def Connection.cache_catalog
    @catalog ||= yield
end

.default ⇒ Object 



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# File 'lib/janko/connection.rb', line 14

def Connection.default
    if Kernel.const_defined?("ActiveRecord::Base")
        new(Kernel.const_get("ActiveRecord::Base"))
    else
        raise("No default connection available.")
    end
end

.reset_cached_catalog ⇒ Object 



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# File 'lib/janko/connection.rb', line 26

def Connection.reset_cached_catalog
    @catalog = nil
    self
end

Instance Method Details

#catalog ⇒ Object

dba.stackexchange.com/questions/22362/ www.postgresql.org/docs/9.3/static/catalog-pg-attribute.html www.postgresql.org/docs/9.3/static/catalog-pg-attrdef.html



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# File 'lib/janko/connection.rb', line 51

def catalog
    Connection.cache_catalog do
        result = backend.exec(<<-END)
            SELECT relname, attname, typname, pg_get_expr(adbin, 0)
            FROM pg_class
            LEFT JOIN pg_namespace ON (
                pg_class.relnamespace = pg_namespace.oid)
            LEFT JOIN pg_attribute ON (
                pg_class.oid = pg_attribute.attrelid)
            LEFT JOIN pg_attrdef ON (
                pg_attribute.attrelid = pg_attrdef.adrelid
                AND pg_attribute.attnum = pg_attrdef.adnum)
            LEFT JOIN pg_type ON (
                pg_attribute.atttypid = pg_type.oid)
            WHERE pg_class.relkind IN ('r','')
                AND pg_namespace.nspname
                    NOT IN ('pg_catalog', 'pg_toast')
                AND pg_table_is_visible(pg_class.oid)
                AND attnum > 0
                AND NOT attisdropped;
        END

        output = {}
        result.each_row do |row|
            output[row[0]] ||= {}
            output[row[0]][row[1]] = { type: row[2], default: row[3] }
        end
        output
    end
end

#column_default(table, column) ⇒ Object 



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# File 'lib/janko/connection.rb', line 90

def column_default(table, column)
    catalog[table][column][:default]
end

#column_list(table) ⇒ Object 



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# File 'lib/janko/connection.rb', line 82

def column_list(table)
    catalog[table].keys
end

#column_type(table, column) ⇒ Object 



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# File 'lib/janko/connection.rb', line 86

def column_type(table, column)
    catalog[table][column][:type]
end

#failed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/janko/connection.rb', line 44

def failed?
    backend.transaction_status >= 3
end

#in_transaction? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/janko/connection.rb', line 40

def in_transaction?
    backend.transaction_status > 0
end