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
293 def fetch_rows(sql)
294   execute(sql) do |r|
295     i = -1
296     cps = db.conversion_procs
297     cols = r.fetch_fields.map do |f| 
298       # Pretend tinyint is another integer type if its length is not 1, to
299       # avoid casting to boolean if convert_tinyint_to_bool is set.
300       type_proc = f.type == 1 && cast_tinyint_integer?(f) ? cps[2] : cps[f.type]
301       [output_identifier(f.name), type_proc, i+=1]
302     end
303     self.columns = cols.map(&:first)
304     if opts[:split_multiple_result_sets]
305       s = []
306       yield_rows(r, cols){|h| s << h}
307       yield s
308     else
309       yield_rows(r, cols){|h| yield h}
310     end
311   end
312   self
313 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
316 def graph(*)
317   raise(Error, "Can't graph a dataset that splits multiple result sets") if opts[:split_multiple_result_sets]
318   super
319 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
330 def split_multiple_result_sets
331   raise(Error, "Can't split multiple statements on a graphed dataset") if opts[:graph]
332   ds = clone(:split_multiple_result_sets=>true)
333   ds = ds.with_row_proc(proc{|x| x.map{|h| row_proc.call(h)}}) if row_proc
334   ds
335 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
342 def cast_tinyint_integer?(field)
343   field.length != 1
344 end
execute(sql, opts=OPTS) click to toggle source
Calls superclass method Sequel::Dataset#execute
    # File lib/sequel/adapters/mysql.rb
346 def execute(sql, opts=OPTS)
347   opts = Hash[opts]
348   opts[:type] = :select
349   super
350 end
literal_string_append(sql, v) click to toggle source

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

    # File lib/sequel/adapters/mysql.rb
353 def literal_string_append(sql, v)
354   sql << "'" << ::Mysql.quote(v) << "'"
355 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
359 def yield_rows(r, cols)
360   while row = r.fetch_row
361     h = {}
362     cols.each{|n, p, i| v = row[i]; h[n] = (v && p) ? p.call(v) : v}
363     yield h
364   end
365 end