module Sequel::Plugins::PreparedStatements::ClassMethods

Private Instance Methods

cached_prepared_statement(type, subtype) { || ... } click to toggle source

If a prepared statement has already been cached for the given type and subtype, return it. Otherwise, yield to the block to get the prepared statement, and cache it.

    # File lib/sequel/plugins/prepared_statements.rb
103 def cached_prepared_statement(type, subtype)
104   h = @prepared_statements[type]
105   Sequel.synchronize do
106     if v = h[subtype]
107       return v
108     end
109   end
110   ps = yield
111   Sequel.synchronize{h[subtype] = ps}
112 end
prepare_explicit_statement(ds, type, vals=OPTS) click to toggle source

Create a prepared statement, but modify the SQL used so that the model’s columns are explicitly selected instead of using *, assuming that the dataset selects from a single table.

   # File lib/sequel/plugins/prepared_statements.rb
43 def prepare_explicit_statement(ds, type, vals=OPTS)
44   s = ds.opts[:returning]
45   if !s || s.empty?
46     ds = ds.returning(*columns.map{|c| Sequel.identifier(c)})
47   end 
48   
49   prepare_statement(ds, type, vals)
50 end
prepare_statement(ds, type, vals=OPTS) click to toggle source

Create a prepared statement based on the given dataset with a unique name for the given type of query and values.

   # File lib/sequel/plugins/prepared_statements.rb
54 def prepare_statement(ds, type, vals=OPTS)
55   ds.clone(:log_sql=>true).prepare(type, :"smpsp_#{NEXT.call}", vals)
56 end
prepared_columns(cols) click to toggle source

Return a sorted array of columns for use as a hash key.

   # File lib/sequel/plugins/prepared_statements.rb
59 def prepared_columns(cols)
60   cols.sort
61 end
prepared_insert(cols) click to toggle source

Return a prepared statement that can be used to insert a row using the given columns.

   # File lib/sequel/plugins/prepared_statements.rb
64 def prepared_insert(cols)
65   cached_prepared_statement(:insert, prepared_columns(cols)){prepare_statement(dataset, :insert, prepared_statement_key_hash(cols))}
66 end
prepared_insert_select(cols) click to toggle source

Return a prepared statement that can be used to insert a row using the given columns and return that column values for the row created.

   # File lib/sequel/plugins/prepared_statements.rb
70 def prepared_insert_select(cols)
71   cached_prepared_statement(:insert_select, prepared_columns(cols)){prepare_explicit_statement(naked.clone(:server=>dataset.opts.fetch(:server, :default)), :insert_select, prepared_statement_key_hash(cols))}
72 end
prepared_statement_key_array(keys) click to toggle source

Return an array of two element arrays with the column symbol as the first entry and the placeholder symbol as the second entry.

   # File lib/sequel/plugins/prepared_statements.rb
76 def prepared_statement_key_array(keys)
77   if dataset.requires_placeholder_type_specifiers?
78     sch = db_schema
79     Array(keys).map do |k|
80       if (s = sch[k]) && (t = s[:type])
81         [k, :"$#{k}__#{t}"]
82       else
83         [k, :"$#{k}"]
84       end
85     end
86   else
87     Array(keys).map{|k| [k, :"$#{k}"]}
88   end
89 end
prepared_statement_key_hash(keys) click to toggle source

Return a hash mapping column symbols to placeholder symbols.

   # File lib/sequel/plugins/prepared_statements.rb
92 def prepared_statement_key_hash(keys)
93   Hash[*(prepared_statement_key_array(keys).flatten)]
94 end
prepared_update(cols) click to toggle source

Return a prepared statement that can be used to update row using the given columns.

   # File lib/sequel/plugins/prepared_statements.rb
97 def prepared_update(cols)
98   cached_prepared_statement(:update, prepared_columns(cols)){prepare_statement(where(prepared_statement_key_array(primary_key)), :update, prepared_statement_key_hash(cols))}
99 end
use_prepared_statements_for_pk_lookup?() click to toggle source

Whether to use prepared statements for lookups by primary key. True if the default primary key lookup isn’t optimized.

    # File lib/sequel/plugins/prepared_statements.rb
116 def use_prepared_statements_for_pk_lookup?
117   !@fast_pk_lookup_sql && !dataset.joined_dataset?
118 end