All the concrete database adapters follow the interface laid down in this class. You can use this interface directly by borrowing the database connection from the Base with Base.connection.
Most of the methods in the adapter are useful during migrations. Most notably, SchemaStatements#create_table, SchemaStatements#drop_table, SchemaStatements#add_index, SchemaStatements#remove_index, SchemaStatements#add_column, SchemaStatements#change_column and SchemaStatements#remove_column are very useful.
- active?
- adapter_name
- disconnect!
- format_log_entry
- log
- log_info
- prefetch_primary_key?
- raw_connection
- reconnect!
- supports_count_distinct?
- supports_migrations?
- verify!
Is this connection active and ready to perform queries?
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 66
66: def active?
67: @active != false
68: end
Returns the human-readable name of the adapter. Use mixed case - one can always use downcase if needed.
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 33
33: def adapter_name
34: 'Abstract'
35: end
Close this connection
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 76
76: def disconnect!
77: @active = false
78: end
Should primary key values be selected from their corresponding sequence before the insert statement? If true, next_sequence_value is called before each insert to set the record’s primary key. This is false for all adapters but Firebird.
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 53
53: def prefetch_primary_key?(table_name = nil)
54: false
55: end
Provides access to the underlying database connection. Useful for when you need to call a proprietary method such as postgresql’s lo_* methods
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 93
93: def raw_connection
94: @connection
95: end
Close this connection and open a new one in its place.
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 71
71: def reconnect!
72: @active = true
73: end
Does this adapter support using DISTINCT within COUNT? This is true for all adapters except sqlite.
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 45
45: def supports_count_distinct?
46: true
47: end
Does this adapter support migrations? Backend specific, as the abstract adapter always returns false.
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 39
39: def supports_migrations?
40: false
41: end
Lazily verify this connection, calling +active?+ only if it hasn’t been called for timeout seconds.
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 82
82: def verify!(timeout)
83: now = Time.now.to_i
84: if (now - @last_verification) > timeout
85: reconnect! unless active?
86: @last_verification = now
87: end
88: end
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 134
134: def format_log_entry(message, dump = nil)
135: if ActiveRecord::Base.colorize_logging
136: if @@row_even
137: @@row_even = false
138: message_color, dump_color = "4;36;1", "0;1"
139: else
140: @@row_even = true
141: message_color, dump_color = "4;35;1", "0"
142: end
143:
144: log_entry = " \e[#{message_color}m#{message}\e[0m "
145: log_entry << "\e[#{dump_color}m%#{String === dump ? 's' : 'p'}\e[0m" % dump if dump
146: log_entry
147: else
148: "%s %s" % [message, dump]
149: end
150: end
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 98
98: def log(sql, name)
99: if block_given?
100: if @logger and @logger.level <= Logger::INFO
101: result = nil
102: seconds = Benchmark.realtime { result = yield }
103: @runtime += seconds
104: log_info(sql, name, seconds)
105: result
106: else
107: yield
108: end
109: else
110: log_info(sql, name, 0)
111: nil
112: end
113: rescue Exception => e
114: # Log message and raise exception.
115: # Set last_verfication to 0, so that connection gets verified
116: # upon reentering the request loop
117: @last_verification = 0
118: message = "#{e.class.name}: #{e.message}: #{sql}"
119: log_info(message, name, 0)
120: raise ActiveRecord::StatementInvalid, message
121: end
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# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 123
123: def log_info(sql, name, runtime)
124: return unless @logger
125:
126: @logger.debug(
127: format_log_entry(
128: "#{name.nil? ? "SQL" : name} (#{sprintf("%f", runtime)})",
129: sql.gsub(/ +/, " ")
130: )
131: )
132: end