Module: Sequel::MySQL::DatasetMethods

Included in:
DataObjects::MySQL::Dataset, JDBC::MySQL::Dataset, Dataset
Defined in:
lib/sequel/adapters/shared/mysql.rb

Overview

Dataset methods shared by datasets that use MySQL databases.

Constant Summary collapse

BOOL_TRUE = 
'1'.freeze
BOOL_FALSE = 
'0'.freeze
TIMESTAMP_FORMAT = 
"'%Y-%m-%d %H:%M:%S'".freeze
COMMA_SEPARATOR = 
', '.freeze
SELECT_CLAUSE_ORDER = 
%w'distinct columns from join where group having compounds order limit'.freeze

Instance Method Summary collapse

Instance Method Details

#complex_expression_sql(op, args) ⇒ Object

MySQL specific syntax for LIKE/REGEXP searches, as well as string concatenation.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 207

def complex_expression_sql(op, args)
  case op
  when :~, :'!~', :'~*', :'!~*', :LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE'
    "(#{literal(args.at(0))} #{'NOT ' if [:'NOT LIKE', :'NOT ILIKE', :'!~', :'!~*'].include?(op)}#{[:~, :'!~', :'~*', :'!~*'].include?(op) ? 'REGEXP' : 'LIKE'} #{'BINARY ' if [:~, :'!~', :LIKE, :'NOT LIKE'].include?(op)}#{literal(args.at(1))})"
  when :'||'
    if args.length > 1
      "CONCAT(#{args.collect{|a| literal(a)}.join(', ')})"
    else
      literal(args.at(0))
    end
  else
    super(op, args)
  end
end

#delete_sql ⇒ Object

MySQL supports ORDER and LIMIT clauses in DELETE statements.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 223

def delete_sql
  sql = super
  sql << " ORDER BY #{expression_list(opts[:order])}" if opts[:order]
  sql << " LIMIT #{opts[:limit]}" if opts[:limit]
  sql
end

#full_text_search(cols, terms, opts = {}) ⇒ Object

Adds full text filter



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# File 'lib/sequel/adapters/shared/mysql.rb', line 231

def full_text_search(cols, terms, opts = {})
  filter(full_text_sql(cols, terms, opts))
end

#full_text_sql(cols, term, opts = {}) ⇒ Object

MySQL specific full text search syntax.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 236

def full_text_sql(cols, term, opts = {})
  "MATCH #{literal(Array(cols))} AGAINST (#{literal(Array(term).join(' '))}#{" IN BOOLEAN MODE" if opts[:boolean]})"
end

#having(*cond, &block) ⇒ Object

MySQL allows HAVING clause on ungrouped datasets.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 241

def having(*cond, &block)
  _filter(:having, *cond, &block)
end

#insert_ignore ⇒ Object

Sets up multi_insert or import to use INSERT IGNORE. Useful if you have a unique key and want to just skip inserting rows that violate the unique key restriction.

Example:

dataset.insert_ignore.multi_insert(

[{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]

)

INSERT IGNORE INTO tablename (name, value) VALUES (a, 1), (b, 2)



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# File 'lib/sequel/adapters/shared/mysql.rb', line 275

def insert_ignore
  clone(:insert_ignore=>true)
end

#join_table(type, table, expr = nil, table_alias = {}) ⇒ Object

Transforms an CROSS JOIN to an INNER JOIN if the expr is not nil. Raises an error on use of :full_outer type, since MySQL doesn’t support it.

Raises:



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# File 'lib/sequel/adapters/shared/mysql.rb', line 247

def join_table(type, table, expr=nil, table_alias={})
  type = :inner if (type == :cross) && !expr.nil?
  raise(Sequel::Error, "MySQL doesn't support FULL OUTER JOIN") if type == :full_outer
  super(type, table, expr, table_alias)
end

#join_type_sql(join_type) ⇒ Object

Transforms :natural_inner to NATURAL LEFT JOIN and straight to STRAIGHT_JOIN.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 255

def join_type_sql(join_type)
  case join_type
  when :straight then 'STRAIGHT_JOIN'
  when :natural_inner then 'NATURAL LEFT JOIN'
  else super
  end
end

#multi_insert_sql(columns, values) ⇒ Object

MySQL specific syntax for inserting multiple values at once.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 308

def multi_insert_sql(columns, values)
  values = values.map {|r| literal(Array(r))}.join(COMMA_SEPARATOR)
  ["#{insert_sql_base}#{source_list(@opts[:from])} (#{identifier_list(columns)}) VALUES #{values}#{insert_sql_suffix}"]
end

#on_duplicate_key_update(*args) ⇒ Object

Sets up multi_insert or import to use ON DUPLICATE KEY UPDATE If you pass no arguments, ALL fields will be updated with the new values. If you pass the fields you want then ONLY those field will be updated.

Useful if you have a unique key and want to update inserting rows that violate the unique key restriction.

Examples:

dataset.on_duplicate_key_update.multi_insert(

[{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]

)

INSERT INTO tablename (name, value) VALUES (a, 1), (b, 2) ON DUPLICATE KEY UPDATE name=VALUES(name), value=VALUES(value)

dataset.on_duplicate_key_update(:value).multi_insert(

[{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]

)

INSERT INTO tablename (name, value) VALUES (a, 1), (b, 2) ON DUPLICATE KEY UPDATE value=VALUES(value)



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# File 'lib/sequel/adapters/shared/mysql.rb', line 303

def on_duplicate_key_update(*args)
  clone(:on_duplicate_key_update => args)
end

#quoted_identifier(c) ⇒ Object

MySQL uses the nonstandard ‘ (backtick) for quoting identifiers.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 314

def quoted_identifier(c)
  "`#{c}`"
end

#replace_sql(*values) ⇒ Object

MySQL specific syntax for REPLACE (aka UPSERT, or update if exists, insert if it doesn’t).



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# File 'lib/sequel/adapters/shared/mysql.rb', line 320

def replace_sql(*values)
  from = source_list(@opts[:from])
  if values.empty?
    "REPLACE INTO #{from} DEFAULT VALUES"
  else
    values = values[0] if values.size == 1
    
    case values
    when Array
      if values.empty?
        "REPLACE INTO #{from} DEFAULT VALUES"
      else
        "REPLACE INTO #{from} VALUES #{literal(values)}"
      end
    when Hash
      if values.empty?
        "REPLACE INTO #{from} DEFAULT VALUES"
      else
        fl, vl = [], []
        values.each {|k, v| fl << literal(k.is_a?(String) ? k.to_sym : k); vl << literal(v)}
        "REPLACE INTO #{from} (#{fl.join(COMMA_SEPARATOR)}) VALUES (#{vl.join(COMMA_SEPARATOR)})"
      end
    when Dataset
      "REPLACE INTO #{from} #{literal(values)}"
    else
      if values.respond_to?(:values)
        replace_sql(values.values)
      else  
        "REPLACE INTO #{from} VALUES (#{literal(values)})"
      end
    end
  end
end

#supports_distinct_on? ⇒ Boolean

does not support DISTINCT ON

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mysql.rb', line 355

def supports_distinct_on?
  false
end

#supports_intersect_except? ⇒ Boolean

MySQL does not support INTERSECT or EXCEPT

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/mysql.rb', line 360

def supports_intersect_except?
  false
end

#update_sql(values) ⇒ Object

MySQL supports ORDER and LIMIT clauses in UPDATE statements.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 365

def update_sql(values)
  sql = super
  sql << " ORDER BY #{expression_list(opts[:order])}" if opts[:order]
  sql << " LIMIT #{opts[:limit]}" if opts[:limit]
  sql
end