Module | Sequel::Dataset::PreparedStatementMethods |
In: |
lib/sequel/adapters/sqlite.rb
lib/sequel/adapters/mysql.rb lib/sequel/adapters/jdbc.rb lib/sequel/adapters/postgres.rb lib/sequel/dataset/prepared_statements.rb |
Backbone of the prepared statement support. Grafts bind variable support into datasets by hijacking literal and using placeholders. By default, emulates prepared statements and bind variables by taking the hash of bind variables and directly substituting them into the query, which works on all databases, as it is no different from using the dataset without bind variables.
PLACEHOLDER_RE | = | /\A\$(.*)\z/ |
prepared_args | [RW] | The array/hash of bound variable placeholder names. |
prepared_modify_values | [RW] | The argument to supply to insert and update, which may use placeholders specified by prepared_args |
prepared_type | [RW] | The type of prepared statement, should be one of :select, :first, :insert, :update, or :delete |
Sets the prepared_args to the given hash and runs the prepared statement.
# File lib/sequel/dataset/prepared_statements.rb, line 72 72: def call(bind_vars={}, &block) 73: bind(bind_vars).run(&block) 74: end
Programmer friendly string showing this is a prepared statement, with the prepared SQL it represents (which in general won‘t have substituted variables).
# File lib/sequel/dataset/prepared_statements.rb, line 110 110: def inspect 111: "<#{self.class.name}/PreparedStatement #{prepared_sql.inspect}>" 112: end
Changes the values of symbols if they start with $ and prepared_args is present. If so, they are considered placeholders, and they are substituted using prepared_arg.
# File lib/sequel/dataset/prepared_statements.rb, line 98 98: def literal_symbol(v) 99: if @opts[:bind_vars] and match = PLACEHOLDER_RE.match(v.to_s) 100: s = match[1].to_sym 101: prepared_arg?(s) ? literal(prepared_arg(s)) : v 102: else 103: super 104: end 105: end
Returns the SQL for the prepared statement, depending on the type of the statement and the prepared_modify_values.
# File lib/sequel/dataset/prepared_statements.rb, line 78 78: def prepared_sql 79: case @prepared_type 80: when :select, :all 81: select_sql 82: when :first 83: clone(:limit=>1).select_sql 84: when :insert_select 85: clone(:returning=>nil).insert_sql(*@prepared_modify_values) 86: when :insert 87: insert_sql(*@prepared_modify_values) 88: when :update 89: update_sql(*@prepared_modify_values) 90: when :delete 91: delete_sql 92: end 93: end
Run the method based on the type of prepared statement, with :select running all to get all of the rows, and the other types running the method with the same name as the type.
# File lib/sequel/dataset/prepared_statements.rb, line 119 119: def run(&block) 120: case @prepared_type 121: when :select, :all 122: all(&block) 123: when :insert_select 124: meta_def(:select_sql){prepared_sql} 125: first 126: when :first 127: first 128: when :insert 129: insert(*@prepared_modify_values) 130: when :update 131: update(*@prepared_modify_values) 132: when :delete 133: delete 134: end 135: end