module Sequel::Database::SplitAlterTable
Private Instance Methods
apply_alter_table(name, ops)
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Preprocess the array of operations. If it looks like some operations depend on results of earlier operations and may require reloading the schema to work correctly, split those operations into separate lists, and between each list, remove the cached schema so that the later operations deal with the then current table schema.
# File lib/sequel/adapters/utils/split_alter_table.rb 11 def apply_alter_table(name, ops) 12 modified_columns = [] 13 op_groups = [[]] 14 ops.each do |op| 15 case op[:op] 16 when :add_column, :set_column_type, :set_column_null, :set_column_default 17 if modified_columns.include?(op[:name]) 18 op_groups << [] 19 else 20 modified_columns << op[:name] 21 end 22 when :rename_column 23 if modified_columns.include?(op[:name]) || modified_columns.include?(op[:new_name]) 24 op_groups << [] 25 end 26 modified_columns << op[:name] unless modified_columns.include?(op[:name]) 27 modified_columns << op[:new_name] unless modified_columns.include?(op[:new_name]) 28 end 29 if split_alter_table_op?(op) 30 op_groups << [] 31 end 32 op_groups.last << op 33 end 34 35 op_groups.each do |opgs| 36 next if opgs.empty? 37 alter_table_sql_list(name, opgs).each{|sql| execute_ddl(sql)} 38 remove_cached_schema(name) 39 end 40 end
split_alter_table_op?(op)
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Whether the given alter table op should start a new group.
# File lib/sequel/adapters/utils/split_alter_table.rb 43 def split_alter_table_op?(op) 44 false 45 end