Class: SQLite3::ResultSet

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/sqlite3/resultset.rb

Overview

The ResultSet object encapsulates the enumerability of a query’s output. It is a simple cursor over the data that the query returns. It will very rarely (if ever) be instantiated directly. Instead, client’s should obtain a ResultSet instance via Statement#execute.

Defined Under Namespace

Classes: ArrayWithTypes, ArrayWithTypesAndFields, HashWithTypes

Instance Method Summary collapse

Constructor Details

#initialize(db, stmt) ⇒ ResultSet

Create a new ResultSet attached to the given database, using the given sql text.



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# File 'lib/sqlite3/resultset.rb', line 34

def initialize db, stmt
  @db   = db
  @stmt = stmt
end

Instance Method Details

#close ⇒ Object

Closes the statement that spawned this result set. Use with caution! Closing a result set will automatically close any other result sets that were spawned from the same statement.



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# File 'lib/sqlite3/resultset.rb', line 105

def close
  @stmt.close
end

#closed? ⇒ Boolean

Queries whether the underlying statement has been closed or not.

Returns:

  • (Boolean) 


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# File 'lib/sqlite3/resultset.rb', line 110

def closed?
  @stmt.closed?
end

#columns ⇒ Object

Returns the names of the columns returned by this result set.



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# File 'lib/sqlite3/resultset.rb', line 120

def columns
  @stmt.columns
end

#each(&block) ⇒ Object

Required by the Enumerable mixin. Provides an internal iterator over the rows of the result set.



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# File 'lib/sqlite3/resultset.rb', line 96

def each( &block )
  while node = self.next
    yield node
  end
end

#eof? ⇒ Boolean

Query whether the cursor has reached the end of the result set or not.

Returns:

  • (Boolean) 


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# File 'lib/sqlite3/resultset.rb', line 48

def eof?
  @stmt.done?
end

#next ⇒ Object

Obtain the next row from the cursor. If there are no more rows to be had, this will return nil. If type translation is active on the corresponding database, the values in the row will be translated according to their types.

The returned value will be an array, unless Database#results_as_hash has been set to true, in which case the returned value will be a hash.

For arrays, the column names are accessible via the fields property, and the column types are accessible via the types property.

For hashes, the column names are the keys of the hash, and the column types are accessible via the types property.



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# File 'lib/sqlite3/resultset.rb', line 65

def next
  row = @stmt.step
  return nil if @stmt.done?

  if @db.type_translation
    row = @stmt.types.zip(row).map do |type, value|
      @db.translator.translate( type, value )
    end
  end

  if @db.results_as_hash
    new_row = HashWithTypes[*@stmt.columns.zip(row).flatten]
    row.each_with_index { |value,idx|
      new_row[idx] = value
    }
    row = new_row
  else
    if row.respond_to?(:fields)
      row = ArrayWithTypes.new(row)
    else
      row = ArrayWithTypesAndFields.new(row)
    end
    row.fields = @stmt.columns
  end

  row.types = @stmt.types
  row
end

#reset(*bind_params) ⇒ Object

Reset the cursor, so that a result set which has reached end-of-file can be rewound and reiterated.



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# File 'lib/sqlite3/resultset.rb', line 41

def reset( *bind_params )
  @stmt.reset!
  @stmt.bind_params( *bind_params )
  @eof = false
end

#types ⇒ Object

Returns the types of the columns returned by this result set.



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# File 'lib/sqlite3/resultset.rb', line 115

def types
  @stmt.types
end