Module: Sequel::Sequel3DatasetMethods

Defined in:
lib/sequel/extensions/sequel_3_dataset_methods.rb

Constant Summary collapse

COMMA =
Dataset::COMMA

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#db=(value) ⇒ Object (writeonly)

The database related to this dataset. This is the Database instance that will execute all of this dataset's queries.


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# File 'lib/sequel/extensions/sequel_3_dataset_methods.rb', line 28

def db=(value)
  @db = value
end

#opts=(value) ⇒ Object (writeonly)

The hash of options for this dataset, keys are symbols.


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# File 'lib/sequel/extensions/sequel_3_dataset_methods.rb', line 31

def opts=(value)
  @opts = value
end

Instance Method Details

#[]=(conditions, values) ⇒ Object

Update all records matching the conditions with the values specified. Returns the number of rows affected.

DB[:table][:id=>1] = {:id=>2} # UPDATE table SET id = 2 WHERE id = 1
# => 1 # number of rows affected

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# File 'lib/sequel/extensions/sequel_3_dataset_methods.rb', line 38

def []=(conditions, values)
  filter(conditions).update(values)
end

#insert_multiple(array, &block) ⇒ Object

Inserts multiple values. If a block is given it is invoked for each item in the given array before inserting it. See multi_insert as a possibly faster version that may be able to insert multiple records in one SQL statement (if supported by the database). Returns an array of primary keys of inserted rows.

DB[:table].insert_multiple([{:x=>1}, {:x=>2}])
# => [4, 5]
# INSERT INTO table (x) VALUES (1)
# INSERT INTO table (x) VALUES (2)

DB[:table].insert_multiple([{:x=>1}, {:x=>2}]){|row| row[:y] = row[:x] * 2; row }
# => [6, 7]
# INSERT INTO table (x, y) VALUES (1, 2)
# INSERT INTO table (x, y) VALUES (2, 4)

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# File 'lib/sequel/extensions/sequel_3_dataset_methods.rb', line 57

def insert_multiple(array, &block)
  if block
    array.map{|i| insert(block.call(i))}
  else
    array.map{|i| insert(i)}
  end
end

#qualify_to(table) ⇒ Object

Return a copy of the dataset with unqualified identifiers in the SELECT, WHERE, GROUP, HAVING, and ORDER clauses qualified by the given table. If no columns are currently selected, select all columns of the given table.

DB[:items].filter(:id=>1).qualify_to(:i)
# SELECT i.* FROM items WHERE (i.id = 1)

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# File 'lib/sequel/extensions/sequel_3_dataset_methods.rb', line 72

def qualify_to(table)
  qualify(table)
end

#qualify_to_first_sourceObject

Qualify the dataset to its current first source. This is useful if you have unqualified identifiers in the query that all refer to the first source, and you want to join to another table which has columns with the same name as columns in the current dataset. See qualify_to.

DB[:items].filter(:id=>1).qualify_to_first_source
# SELECT items.* FROM items WHERE (items.id = 1)

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# File 'lib/sequel/extensions/sequel_3_dataset_methods.rb', line 84

def qualify_to_first_source
  qualify
end

#set(*args) ⇒ Object

Alias for update, but not aliased directly so subclasses don't have to override both methods.


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# File 'lib/sequel/extensions/sequel_3_dataset_methods.rb', line 90

def set(*args)
  update(*args)
end

#to_csv(include_column_titles = true) ⇒ Object

Returns a string in CSV format containing the dataset records. By default the CSV representation includes the column titles in the first line. You can turn that off by passing false as the include_column_titles argument.

This does not use a CSV library or handle quoting of values in any way. If any values in any of the rows could include commas or line endings, you shouldn't use this.

puts DB[:table].to_csv # SELECT * FROM table
# id,name
# 1,Jim
# 2,Bob

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# File 'lib/sequel/extensions/sequel_3_dataset_methods.rb', line 107

def to_csv(include_column_titles = true)
  n = naked
  cols = n.columns
  csv = ''
  csv << "#{cols.join(COMMA)}\r\n" if include_column_titles
  n.each{|r| csv << "#{cols.collect{|c| r[c]}.join(COMMA)}\r\n"}
  csv
end