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
  @driver = @db.driver
  @stmt = stmt
  commence
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 155

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 160

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 170

def columns
  @stmt.columns
end

#each ⇒ 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 146

def each
  while row=self.next
    yield row
  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 72

def eof?
  @eof
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 89

def next
  return nil if @eof

  @stmt.must_be_open!

  unless @first_row
    result = @driver.step(@stmt.handle)
    check result
  end

  @first_row = false

  unless @eof
    row = []
    @driver.data_count(@stmt.handle).times do |column|
      type  = @driver.column_type(@stmt.handle, column)

      if type == Constants::ColumnType::TEXT
        row << @driver.column_text(@stmt.handle, column)
      elsif type == Constants::ColumnType::NULL
        row << nil
      elsif type == Constants::ColumnType::BLOB
        row << @driver.column_blob(@stmt.handle, column)
      else
        row << @driver.column_text(@stmt.handle, column)
      end
    end

    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).to_a.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

    return row
  end

  nil
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 62

def reset(*bind_params)
  @stmt.must_be_open!
  @stmt.reset!(false)
  @driver.reset(@stmt.handle)
  @stmt.bind_params(*bind_params)
  @eof = false
  commence
end

#types ⇒ Object

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



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# File 'lib/sqlite3/resultset.rb', line 165

def types
  @stmt.types
end