class Sequel::MySQL::Dataset

Public Instance Methods

fetch_rows(sql) { |s| ... } click to toggle source

Yield all rows matching this dataset. If the dataset is set to split multiple statements, yield arrays of hashes one per statement instead of yielding results for all statements as hashes.

    # File lib/sequel/adapters/mysql.rb
280 def fetch_rows(sql)
281   execute(sql) do |r|
282     i = -1
283     cps = db.conversion_procs
284     cols = r.fetch_fields.map do |f| 
285       # Pretend tinyint is another integer type if its length is not 1, to
286       # avoid casting to boolean if convert_tinyint_to_bool is set.
287       type_proc = f.type == 1 && cast_tinyint_integer?(f) ? cps[2] : cps[f.type]
288       [output_identifier(f.name), type_proc, i+=1]
289     end
290     self.columns = cols.map(&:first)
291     if opts[:split_multiple_result_sets]
292       s = []
293       yield_rows(r, cols){|h| s << h}
294       yield s
295     else
296       yield_rows(r, cols){|h| yield h}
297     end
298   end
299   self
300 end
graph(*) click to toggle source

Don't allow graphing a dataset that splits multiple statements

Calls superclass method Sequel::Dataset#graph
    # File lib/sequel/adapters/mysql.rb
303 def graph(*)
304   raise(Error, "Can't graph a dataset that splits multiple result sets") if opts[:split_multiple_result_sets]
305   super
306 end
split_multiple_result_sets() click to toggle source

Makes each yield arrays of rows, with each array containing the rows for a given result set. Does not work with graphing. So you can submit SQL with multiple statements and easily determine which statement returned which results.

Modifies the row_proc of the returned dataset so that it still works as expected (running on the hashes instead of on the arrays of hashes). If you modify the row_proc afterward, note that it will receive an array of hashes instead of a hash.

    # File lib/sequel/adapters/mysql.rb
317 def split_multiple_result_sets
318   raise(Error, "Can't split multiple statements on a graphed dataset") if opts[:graph]
319   ds = clone(:split_multiple_result_sets=>true)
320   ds = ds.with_row_proc(proc{|x| x.map{|h| row_proc.call(h)}}) if row_proc
321   ds
322 end

Private Instance Methods

cast_tinyint_integer?(field) click to toggle source

Whether a tinyint field should be casted as an integer. By default, casts to integer if the field length is not 1. Can be overwritten to make tinyint casting dataset dependent.

    # File lib/sequel/adapters/mysql.rb
329 def cast_tinyint_integer?(field)
330   field.length != 1
331 end
execute(sql, opts=OPTS) click to toggle source
Calls superclass method Sequel::Dataset#execute
    # File lib/sequel/adapters/mysql.rb
333 def execute(sql, opts=OPTS)
334   opts = Hash[opts]
335   opts[:type] = :select
336   super
337 end
literal_string_append(sql, v) click to toggle source

Handle correct quoting of strings using ::MySQL.quote.

    # File lib/sequel/adapters/mysql.rb
340 def literal_string_append(sql, v)
341   sql << "'" << ::Mysql.quote(v) << "'"
342 end
yield_rows(r, cols) { |h| ... } click to toggle source

Yield each row of the given result set r with columns cols as a hash with symbol keys

    # File lib/sequel/adapters/mysql.rb
346 def yield_rows(r, cols)
347   while row = r.fetch_row
348     h = {}
349     cols.each{|n, p, i| v = row[i]; h[n] = (v && p) ? p.call(v) : v}
350     yield h
351   end
352 end