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, clients should obtain a ResultSet instance via Statement#execute.

Defined Under Namespace

Classes: ArrayWithTypes, ArrayWithTypesAndFields, HashWithTypesAndFields

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 72

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

Instance Method Details

#closeObject

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 153

def close
  @stmt.close
end

#closed?Boolean

Queries whether the underlying statement has been closed or not.



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# File 'lib/sqlite3/resultset.rb', line 158

def closed?
  @stmt.closed?
end

#columnsObject

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



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# File 'lib/sqlite3/resultset.rb', line 168

def columns
  @stmt.columns
end

#eachObject

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 136

def each
  while node = self.next
    yield node
  end
end

#each_hashObject

Provides an internal iterator over the rows of the result set where each row is yielded as a hash.



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# File 'lib/sqlite3/resultset.rb', line 144

def each_hash
  while node = next_hash
    yield node
  end
end

#eof?Boolean

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



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# File 'lib/sqlite3/resultset.rb', line 86

def eof?
  @stmt.done?
end

#nextObject

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 103

def next
  if @db.results_as_hash
    return next_hash
  end

  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 row.respond_to?(:fields)
    # FIXME: this can only happen if the translator returns something
    # that responds to `fields`.  Since we're removing the translator
    # in 2.0, we can remove this branch in 2.0.
    row = ArrayWithTypes.new(row)
  else
    # FIXME: the `fields` and `types` methods are deprecated on this
    # object for version 2.0, so we can safely remove this branch
    # as well.
    row = ArrayWithTypesAndFields.new(row)
  end

  row.fields = @stmt.columns
  row.types = @stmt.types
  row
end

#next_hashObject

Return the next row as a hash



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# File 'lib/sqlite3/resultset.rb', line 173

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

  # FIXME: type translation is deprecated, so this can be removed
  # in 2.0
  if @db.type_translation
    row = @stmt.types.zip(row).map do |type, value|
      @db.translator.translate( type, value )
    end
  end

  # FIXME: this can be switched to a regular hash in 2.0
  row = HashWithTypesAndFields[*@stmt.columns.zip(row).flatten]

  # FIXME: these methods are deprecated for version 2.0, so we can remove
  # this code in 2.0
  row.fields = @stmt.columns
  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 79

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

#typesObject

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



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# File 'lib/sqlite3/resultset.rb', line 163

def types
  @stmt.types
end