Module Sequel::Dataset::PreparedStatementMethods
In: lib/sequel/adapters/jdbc.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.

Methods

Included Modules

Sequel::Dataset::UnnumberedArgumentMapper

Constants

PLACEHOLDER_RE = /\A\$(.*)\z/

Attributes

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

Public Instance methods

Sets the prepared_args to the given hash and runs the prepared statement.

[Source]

    # File lib/sequel/dataset/prepared_statements.rb, line 66
66:       def call(bind_vars={}, &block)
67:         bind(bind_vars).run(&block)
68:       end

Programmer friendly string showing this is a prepared statement, with the prepared SQL it represents (which in general won‘t have substituted variables).

[Source]

     # File lib/sequel/dataset/prepared_statements.rb, line 102
102:       def inspect
103:         "<#{self.class.name}/PreparedStatement #{prepared_sql.inspect}>"
104:       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.

[Source]

    # File lib/sequel/dataset/prepared_statements.rb, line 90
90:       def literal_symbol(v)
91:         if @opts[:bind_vars] and match = PLACEHOLDER_RE.match(v.to_s)
92:           v2 = prepared_arg(match[1].to_sym)
93:           v2 ? literal(v2) : v
94:         else
95:           super
96:         end
97:       end

Returns the SQL for the prepared statement, depending on the type of the statement and the prepared_modify_values.

[Source]

    # File lib/sequel/dataset/prepared_statements.rb, line 72
72:       def prepared_sql
73:         case @prepared_type
74:         when :select, :all
75:           select_sql
76:         when :first
77:           clone(:limit=>1).select_sql
78:         when :insert
79:           insert_sql(*@prepared_modify_values)
80:         when :update
81:           update_sql(*@prepared_modify_values)
82:         when :delete
83:           delete_sql
84:         end
85:       end

Protected Instance methods

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.

[Source]

     # File lib/sequel/dataset/prepared_statements.rb, line 111
111:       def run(&block)
112:         case @prepared_type
113:         when :select, :all
114:           all(&block)
115:         when :first
116:           first
117:         when :insert
118:           insert(*@prepared_modify_values)
119:         when :update
120:           update(*@prepared_modify_values)
121:         when :delete
122:           delete
123:         end
124:       end

[Validate]