Module: ActiveRecord::ConnectionAdapters::PostgreSQL::DatabaseStatements

Included in:
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
Defined in:
activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb

Constant Summary collapse

MONEY_COLUMN_TYPE_OID =

The internal PostgreSQL identifier of the money data type.

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BYTEA_COLUMN_TYPE_OID =

The internal PostgreSQL identifier of the BYTEA data type.

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Instance Method Summary collapse

Instance Method Details

#begin_db_transactionObject

Begins a transaction.


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 151

def begin_db_transaction
  execute "BEGIN"
end

#begin_isolated_db_transaction(isolation) ⇒ Object


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 155

def begin_isolated_db_transaction(isolation)
  begin_db_transaction
  execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
end

#commit_db_transactionObject

Commits a transaction.


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 161

def commit_db_transaction
  execute "COMMIT"
end

#exec_delete(sql, name = 'SQL', binds = []) ⇒ Object Also known as: exec_update


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 115

def exec_delete(sql, name = 'SQL', binds = [])
  execute_and_clear(sql, name, binds) {|result| result.cmd_tuples }
end

#exec_insert(sql, name, binds, pk = nil, sequence_name = nil) ⇒ Object


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 136

def exec_insert(sql, name, binds, pk = nil, sequence_name = nil)
  val = exec_query(sql, name, binds)
  if !use_insert_returning? && pk
    unless sequence_name
      table_ref = extract_table_ref_from_insert_sql(sql)
      sequence_name = default_sequence_name(table_ref, pk)
      return val unless sequence_name
    end
    last_insert_id_result(sequence_name)
  else
    val
  end
end

#exec_query(sql, name = 'SQL', binds = [], prepare: false) ⇒ Object


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 102

def exec_query(sql, name = 'SQL', binds = [], prepare: false)
  execute_and_clear(sql, name, binds, prepare: prepare) do |result|
    types = {}
    fields = result.fields
    fields.each_with_index do |fname, i|
      ftype = result.ftype i
      fmod  = result.fmod i
      types[fname] = get_oid_type(ftype, fmod, fname)
    end
    ActiveRecord::Result.new(fields, result.values, types)
  end
end

#exec_rollback_db_transactionObject

Aborts a transaction.


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 166

def exec_rollback_db_transaction
  execute "ROLLBACK"
end

#execute(sql, name = nil) ⇒ Object

Executes an SQL statement, returning a PGresult object on success or raising a PGError exception otherwise. Note: the PGresult object is manually memory managed; if you don't need it specifically, you many want consider the exec_query wrapper.


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 96

def execute(sql, name = nil)
  log(sql, name) do
    @connection.async_exec(sql)
  end
end

#explain(arel, binds = []) ⇒ Object


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 5

def explain(arel, binds = [])
  sql = "EXPLAIN #{to_sql(arel, binds)}"
  PostgreSQL::ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
end

#query(sql, name = nil) ⇒ Object

Queries the database and returns the results in an Array-like object


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 86

def query(sql, name = nil) #:nodoc:
  log(sql, name) do
    result_as_array @connection.async_exec(sql)
  end
end

#result_as_array(res) ⇒ Object

create a 2D array representing the result set


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 44

def result_as_array(res) #:nodoc:
  # check if we have any binary column and if they need escaping
  ftypes = Array.new(res.nfields) do |i|
    [i, res.ftype(i)]
  end

  rows = res.values
  return rows unless ftypes.any? { |_, x|
    x == BYTEA_COLUMN_TYPE_OID || x == MONEY_COLUMN_TYPE_OID
  }

  typehash = ftypes.group_by { |_, type| type }
  binaries = typehash[BYTEA_COLUMN_TYPE_OID] || []
  monies   = typehash[MONEY_COLUMN_TYPE_OID] || []

  rows.each do |row|
    # unescape string passed BYTEA field (OID == 17)
    binaries.each do |index, _|
      row[index] = unescape_bytea(row[index])
    end

    # If this is a money type column and there are any currency symbols,
    # then strip them off. Indeed it would be prettier to do this in
    # PostgreSQLColumn.string_to_decimal but would break form input
    # fields that call value_before_type_cast.
    monies.each do |index, _|
      data = row[index]      # Because money output is formatted according to the locale, there are two
      # cases to consider (note the decimal separators):
      #  (1) $12,345,678.12
      #  (2) $12.345.678,12

      case data
      when /^-?\D+[\d,]+\.\d{2}$/  # (1)
        data.gsub!(/[^-\d.]/, '')
      when /^-?\D+[\d.]+,\d{2}$/  # (2)
        data.gsub!(/[^-\d,]/, '').sub!(/,/, '.')
      end
    end
  end
end

#select_rows(sql, name = nil, binds = []) ⇒ Object

Executes a SELECT query and returns an array of rows. Each row is an array of field values.


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 32

def select_rows(sql, name = nil, binds = [])
  execute_and_clear(sql, name, binds) do |result|
    result.values
  end
end

#select_value(arel, name = nil, binds = []) ⇒ Object


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 10

def select_value(arel, name = nil, binds = [])
  arel, binds = binds_from_relation arel, binds
  sql = to_sql(arel, binds)
  execute_and_clear(sql, name, binds) do |result|
    result.getvalue(0, 0) if result.ntuples > 0 && result.nfields > 0
  end
end

#select_values(arel, name = nil, binds = []) ⇒ Object


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 18

def select_values(arel, name = nil, binds = [])
  arel, binds = binds_from_relation arel, binds
  sql = to_sql(arel, binds)
  execute_and_clear(sql, name, binds) do |result|
    if result.nfields > 0
      result.column_values(0)
    else
      []
    end
  end
end

#sql_for_insert(sql, pk, id_value, sequence_name, binds) ⇒ Object

:nodoc:


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb', line 120

def sql_for_insert(sql, pk, id_value, sequence_name, binds) # :nodoc:
  if pk.nil?    # Extract the table from the insert sql. Yuck.

    table_ref = extract_table_ref_from_insert_sql(sql)
    pk = primary_key(table_ref) if table_ref
  end

  pk = suppress_composite_primary_key(pk)

  if pk && use_insert_returning?
    sql = "#{sql} RETURNING #{quote_column_name(pk)}"
  end

  super
end