Module: RR::ConnectionExtenders::PostgreSQLExtender

Defined in:
lib/rubyrep/connection_extenders/postgresql_extender.rb

Overview

Provides various PostgreSQL specific functionality required by Rubyrep.

Instance Method Summary collapse

Instance Method Details

#column_aware_quote(value, column) ⇒ String

Quotes the value so it can be used in SQL insert / update statements.



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# File 'lib/rubyrep/connection_extenders/postgresql_extender.rb', line 111

def column_aware_quote(value, column)
  quote column.type_cast_for_database value
end

#fixed_type_cast(value, column) ⇒ Object

Casts a value returned from the database back into the according ruby type.



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# File 'lib/rubyrep/connection_extenders/postgresql_extender.rb', line 120

def fixed_type_cast(value, column)
  if column.sql_type == 'bytea' and RUBY_PLATFORM == 'java'
    # Apparently in Java / JRuby binary data are automatically unescaped.
    # So #type_cast_from_database must be prevented from double-unescaping the binary data.
      value
  else
    column.type_cast_from_database value
  end
end

#primary_key_names(table) ⇒ Object

Returns an ordered list of primary key column names of the given table



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# File 'lib/rubyrep/connection_extenders/postgresql_extender.rb', line 33

def primary_key_names(table)
  row = self.select_one("    SELECT relname\n    FROM pg_class\n    WHERE relname = '\#{table}' and relnamespace IN\n      (SELECT oid FROM pg_namespace WHERE nspname in (\#{schemas}))\n  end_sql\n  raise \"table '\#{table}' does not exist\" if row.nil?\n  \n  row = self.select_one(<<-end_sql)\n    SELECT cons.conkey \n    FROM pg_class           rel\n    JOIN pg_constraint      cons ON (rel.oid = cons.conrelid)\n    WHERE cons.contype = 'p' AND rel.relname = '\#{table}' AND rel.relnamespace IN\n      (SELECT oid FROM pg_namespace WHERE nspname in (\#{schemas}))\n  end_sql\n  return [] if row.nil?\n  column_parray = row['conkey']\n  \n  # Change a Postgres Array of attribute numbers\n  # (returned in String form, e. g.: \"{1,2}\") into an array of Integers\n  if column_parray.kind_of?(Array)\n    column_ids = column_parray # in JRuby the attribute numbers are already returned as array\n  else\n    column_ids = column_parray.sub(/^\\{(.*)\\}$/,'\\1').split(',').map {|a| a.to_i}\n  end\n\n  columns = {}\n  rows = self.select_all(<<-end_sql)\n    SELECT attnum, attname\n    FROM pg_class           rel\n    JOIN pg_constraint      cons ON (rel.oid = cons.conrelid)\n    JOIN pg_attribute       attr ON (rel.oid = attr.attrelid and attr.attnum = any (cons.conkey))\n    WHERE cons.contype = 'p' AND rel.relname = '\#{table}' AND rel.relnamespace IN\n      (SELECT oid FROM pg_namespace WHERE nspname in (\#{schemas}))\n  end_sql\n  sorted_columns = []\n  if not rows.nil?\n    rows.each() {|r| columns[r['attnum'].to_i] = r['attname']}\n    sorted_columns = column_ids.map {|column_id| columns[column_id]}\n  end\n  sorted_columns\nend\n")

#referenced_tables(tables) ⇒ Object

Returns for each given table, which other tables it references via foreign key constraints.

  • tables: an array of table names

Returns: a hash with

  • key: name of the referencing table

  • value: an array of names of referenced tables



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# File 'lib/rubyrep/connection_extenders/postgresql_extender.rb', line 83

def referenced_tables(tables)
  rows = self.select_all("    select distinct referencing.relname as referencing_table, referenced.relname as referenced_table\n    from pg_class referencing\n    left join pg_constraint on referencing.oid = pg_constraint.conrelid\n    left join pg_class referenced on pg_constraint.confrelid = referenced.oid\n    where referencing.relkind='r'\n    and referencing.relname in ('\#{tables.join(\"', '\")}')\n    and referencing.relnamespace IN\n      (SELECT oid FROM pg_namespace WHERE nspname in (\#{schemas}))\n  end_sql\n  result = {}\n  rows.each do |row|\n    unless result.include? row['referencing_table']\n      result[row['referencing_table']] = []\n    end\n    if row['referenced_table'] != nil\n      result[row['referencing_table']] << row['referenced_table']\n    end\n  end\n  result\nend\n")

#schemas ⇒ Object

Returns an array of schemas in the current search path.



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# File 'lib/rubyrep/connection_extenders/postgresql_extender.rb', line 11

def schemas
  unless @schemas
    search_path = select_one("show search_path")['search_path']
    @schemas = search_path.split(/,/).map { |p| quote(p.strip) }.join(',')
  end
  @schemas
end

#tables(name = nil) ⇒ Object

*** Monkey patch*** Returns the list of all tables in the schema search path or a specified schema. This overwrites the according ActiveRecord::PostgreSQLAdapter method to make sure that also search paths with spaces work (E. g. ‘public, rr’ instead of only ‘public,rr’)



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# File 'lib/rubyrep/connection_extenders/postgresql_extender.rb', line 24

def tables(name = nil)
  select_all("    SELECT tablename\n      FROM pg_tables\n     WHERE schemaname IN (\#{schemas})\n  SQL\nend\n", name).map { |row| row['tablename'] }