1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
require 'date'
require 'bigdecimal'
require 'bigdecimal/util'
require 'active_support/core_ext/benchmark'
# TODO: Autoload these files
require 'active_record/connection_adapters/abstract/schema_definitions'
require 'active_record/connection_adapters/abstract/schema_statements'
require 'active_record/connection_adapters/abstract/database_statements'
require 'active_record/connection_adapters/abstract/quoting'
require 'active_record/connection_adapters/abstract/connection_pool'
require 'active_record/connection_adapters/abstract/connection_specification'
require 'active_record/connection_adapters/abstract/query_cache'
module ActiveRecord
module ConnectionAdapters # :nodoc:
# ActiveRecord supports multiple database systems. AbstractAdapter and
# related classes form the abstraction layer which makes this possible.
# An AbstractAdapter represents a connection to a database, and provides an
# abstract interface for database-specific functionality such as establishing
# a connection, escaping values, building the right SQL fragments for ':offset'
# and ':limit' options, etc.
#
# All the concrete database adapters follow the interface laid down in this class.
# ActiveRecord::Base.connection returns an AbstractAdapter object, which
# you can use.
#
# Most of the methods in the adapter are useful during migrations. Most
# notably, the instance methods provided by SchemaStatement are very useful.
class AbstractAdapter
include Quoting, DatabaseStatements, SchemaStatements
include QueryCache
include ActiveSupport::Callbacks
define_callbacks :checkout, :checkin
@@row_even = true
def initialize(connection, logger = nil) #:nodoc:
@connection, @logger = connection, logger
@runtime = 0
@last_verification = 0
@query_cache_enabled = false
end
# Returns the human-readable name of the adapter. Use mixed case - one
# can always use downcase if needed.
def adapter_name
'Abstract'
end
# Does this adapter support migrations? Backend specific, as the
# abstract adapter always returns +false+.
def supports_migrations?
false
end
# Can this adapter determine the primary key for tables not attached
# to an ActiveRecord class, such as join tables? Backend specific, as
# the abstract adapter always returns +false+.
def supports_primary_key?
false
end
# Does this adapter support using DISTINCT within COUNT? This is +true+
# for all adapters except sqlite.
def supports_count_distinct?
true
end
# Does this adapter support DDL rollbacks in transactions? That is, would
# CREATE TABLE or ALTER TABLE get rolled back by a transaction? PostgreSQL,
# SQL Server, and others support this. MySQL and others do not.
def supports_ddl_transactions?
false
end
# Does this adapter support savepoints? PostgreSQL and MySQL do, SQLite
# does not.
def supports_savepoints?
false
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.
def prefetch_primary_key?(table_name = nil)
false
end
def reset_runtime #:nodoc:
rt, @runtime = @runtime, 0
rt
end
# QUOTING ==================================================
# Override to return the quoted table name. Defaults to column quoting.
def quote_table_name(name)
quote_column_name(name)
end
# REFERENTIAL INTEGRITY ====================================
# Override to turn off referential integrity while executing <tt>&block</tt>.
def disable_referential_integrity(&block)
yield
end
# CONNECTION MANAGEMENT ====================================
# Checks whether the connection to the database is still active. This includes
# checking whether the database is actually capable of responding, i.e. whether
# the connection isn't stale.
def active?
@active != false
end
# Disconnects from the database if already connected, and establishes a
# new connection with the database.
def reconnect!
@active = true
end
# Disconnects from the database if already connected. Otherwise, this
# method does nothing.
def disconnect!
@active = false
end
# Reset the state of this connection, directing the DBMS to clear
# transactions and other connection-related server-side state. Usually a
# database-dependent operation.
#
# The default implementation does nothing; the implementation should be
# overridden by concrete adapters.
def reset!
# this should be overridden by concrete adapters
end
# Returns true if its safe to reload the connection between requests for development mode.
def requires_reloading?
true
end
# Checks whether the connection to the database is still active (i.e. not stale).
# This is done under the hood by calling <tt>active?</tt>. If the connection
# is no longer active, then this method will reconnect to the database.
def verify!(*ignored)
reconnect! unless active?
end
# Provides access to the underlying database driver for this adapter. For
# example, this method returns a Mysql object in case of MysqlAdapter,
# and a PGconn object in case of PostgreSQLAdapter.
#
# This is useful for when you need to call a proprietary method such as
# PostgreSQL's lo_* methods.
def raw_connection
@connection
end
def open_transactions
@open_transactions ||= 0
end
def increment_open_transactions
@open_transactions ||= 0
@open_transactions += 1
end
def decrement_open_transactions
@open_transactions -= 1
end
def transaction_joinable=(joinable)
@transaction_joinable = joinable
end
def create_savepoint
end
def rollback_to_savepoint
end
def release_savepoint
end
def current_savepoint_name
"active_record_#{open_transactions}"
end
def log_info(sql, name, ms)
if @logger && @logger.debug?
name = '%s (%.1fms)' % [name || 'SQL', ms]
@logger.debug(format_log_entry(name, sql.squeeze(' ')))
end
end
protected
def log(sql, name)
result = nil
ActiveSupport::Notifications.instrument(:sql, :sql => sql, :name => name) do
@runtime += Benchmark.ms { result = yield }
end
result
rescue Exception => e
# Log message and raise exception.
# Set last_verification to 0, so that connection gets verified
# upon reentering the request loop
@last_verification = 0
message = "#{e.class.name}: #{e.message}: #{sql}"
log_info(message, name, 0)
raise translate_exception(e, message)
end
def translate_exception(e, message)
# override in derived class
ActiveRecord::StatementInvalid.new(message)
end
def format_log_entry(message, dump = nil)
if ActiveRecord::Base.colorize_logging
if @@row_even
@@row_even = false
message_color, dump_color = "4;36;1", "0;1"
else
@@row_even = true
message_color, dump_color = "4;35;1", "0"
end
log_entry = " \e[#{message_color}m#{message}\e[0m "
log_entry << "\e[#{dump_color}m%#{String === dump ? 's' : 'p'}\e[0m" % dump if dump
log_entry
else
"%s %s" % [message, dump]
end
end
end
end
end
|