The schema_caching extension adds a few methods to Sequel::Database that make it easy to dump the parsed schema information to a file, and load it from that file. Loading the schema information from a dumped file is faster than parsing it from the database, so this can save bootup time for applications with large numbers of models.
Basic usage in application code:
Sequel.extension :schema_caching DB = Sequel.connect('...') DB.load_schema_cache('/path/to/schema.dump') # load model files
Then, whenever the database schema is modified, write a new cached file. You can do that with bin/sequel‘s -S option:
bin/sequel -S /path/to/schema.dump postgres://...
Alternatively, if you don‘t want to dump the schema information for all tables, and you don‘t worry about race conditions, you can choose to use the following in your application code:
Sequel.extension :schema_caching DB = Sequel.connect('...') DB.load_schema_cache?('/path/to/schema.dump') # load model files DB.dump_schema_cache?('/path/to/schema.dump')
With this method, you just have to delete the schema dump file if the schema is modified, and the application will recreate it for you using just the tables that your models use.
Note that it is up to the application to ensure that the dumped cached schema reflects the current state of the database. Sequel does no checking to ensure this, as checking would take time and the purpose of this code is to take a shortcut.
The cached schema is dumped in Marshal format, since it is the fastest and it handles all ruby objects used in the schema hash. Because of this, you should not attempt to load the schema from a untrusted file.
ADAPTER_MAP | = | {} | Hash of adapters that have been used. The key is the adapter scheme symbol, and the value is the Database subclass. | |
DATABASES | = | [] | Array of all databases to which Sequel has connected. If you are developing an application that can connect to an arbitrary number of databases, delete the database objects from this or they will not get garbage collected. | |
MAJOR | = | 3 | The major version of Sequel. Only bumped for major changes. | |
MINOR | = | 38 | The minor version of Sequel. Bumped for every non-patch level release, generally around once a month. | |
TINY | = | 0 | The tiny version of Sequel. Usually 0, only bumped for bugfix releases that fix regressions from previous versions. | |
VERSION | = | [MAJOR, MINOR, TINY].join('.') | The version of Sequel you are using, as a string (e.g. "2.11.0") | |
COLUMN_REF_RE1 | = | /\A((?:(?!__).)+)__((?:(?!___).)+)___(.+)\z/.freeze | ||
COLUMN_REF_RE2 | = | /\A((?:(?!___).)+)___(.+)\z/.freeze | ||
COLUMN_REF_RE3 | = | /\A((?:(?!__).)+)__(.+)\z/.freeze | ||
BeforeHookFailed | = | HookFailed | Deprecated alias for HookFailed, kept for backwards compatibility | |
DEFAULT_INFLECTIONS_PROC | = | proc do plural(/$/, 's') | Proc that is instance evaled to create the default inflections for both the model inflector and the inflector extension. | |
STRING_TYPES | = | [18, 19, 25, 1042, 1043] | Type OIDs for string types used by PostgreSQL. These types don‘t have conversion procs associated with them (since the data is already in the form of a string). | |
PG_NAMED_TYPES | = | {} unless defined?(PG_NAMED_TYPES) | Hash with type name strings/symbols and callable values for converting PostgreSQL types. Non-builtin types that don‘t have fixed numbers should use this to register conversion procs. | |
PG_TYPES | = | {} unless defined?(PG_TYPES) | Hash with integer keys and callable values for converting PostgreSQL types. | |
MYSQL_TYPES | = | {} | Hash with integer keys and callable values for converting MySQL types. | |
SQLITE_TYPES | = | {} | Hash with string keys and callable values for converting SQLite types. |
autoid | [W] |
Set the autogenerated primary key integer to be returned when running an
insert query. Argument types supported:
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columns | [W] |
Set the columns to set in the dataset when the dataset fetches rows.
Argument types supported:
Array of Symbols: Used for all datasets Array (otherwise): First retrieval gets the first value in the array, second gets the second value, etc.
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convert_invalid_date_time | [RW] |
Whether to convert invalid date time values by default.
Only applies to Sequel::Database instances created after this has been set. |
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convert_two_digit_years | [RW] |
Sequel converts two digit years in Dates
and DateTimes by default, so 01/02/03 is interpreted at January
2nd, 2003, and 12/13/99 is interpreted as December 13, 1999. You can
override this to treat those dates as January 2nd, 0003 and December 13,
0099, respectively, by:
Sequel.convert_two_digit_years = false |
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datetime_class | [RW] |
Sequel can use either Time or
DateTime for times returned from the database. It defaults to
Time. To change it to DateTime:
Sequel.datetime_class = DateTime For ruby versions less than 1.9.2, Time has a limited range (1901 to 2038), so if you use datetimes out of that range, you need to switch to DateTime. Also, before 1.9.2, Time can only handle local and UTC times, not other timezones. Note that Time and DateTime objects have a different API, and in cases where they implement the same methods, they often implement them differently (e.g. + using seconds on Time and days on DateTime). |
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empty_array_handle_nulls | [RW] |
Sets whether or not to attempt to handle NULL values correctly when given
an empty array. By default:
DB[:a].filter(:b=>[]) # SELECT * FROM a WHERE (b != b) DB[:a].exclude(:b=>[]) # SELECT * FROM a WHERE (b = b) However, some databases (e.g. MySQL) will perform very poorly with this type of query. You can set this to false to get the following behavior: DB[:a].filter(:b=>[]) # SELECT * FROM a WHERE 1 = 0 DB[:a].exclude(:b=>[]) # SELECT * FROM a WHERE 1 = 1 This may not handle NULLs correctly, but can be much faster on some databases. |
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fetch | [W] |
Set the hashes to yield by execute when
retrieving rows. Argument types supported:
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numrows | [W] |
Set the number of rows to return from update or delete. Argument types
supported:
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server_version | [RW] | Mock the server version, useful when using the shared adapters | ||||||||||||
use_iso_date_format | [R] | As an optimization, Sequel sets the date style to ISO, so that PostgreSQL provides the date in a known format that Sequel can parse faster. This can be turned off if you require a date style other than ISO. | ||||||||||||
virtual_row_instance_eval | [RW] | For backwards compatibility, has no effect. |
Lets you create a Model subclass with its dataset already set. source should be an instance of one of the following classes:
Database : | Sets the database for this model to source. Generally only useful when subclassing directly from the returned class, where the name of the subclass sets the table name (which is combined with the Database in source to create the dataset to use) |
Dataset : | Sets the dataset for this model to source. |
other : | Sets the table name for this model to source. The class will use the default database for model classes in order to create the dataset. |
The purpose of this method is to set the dataset/database automatically for a model class, if the table name doesn‘t match the implicit name. This is neater than using set_dataset inside the class, doesn‘t require a bogus query for the schema.
# Using a symbol class Comment < Sequel::Model(:something) table_name # => :something end # Using a dataset class Comment < Sequel::Model(DB1[:something]) dataset # => DB1[:something] end # Using a database class Comment < Sequel::Model(DB1) dataset # => DB1[:comments] end
# File lib/sequel/model.rb, line 37 37: def self.Model(source) 38: if Sequel::Model.cache_anonymous_models && (klass = Sequel.synchronize{Model::ANONYMOUS_MODEL_CLASSES[source]}) 39: return klass 40: end 41: klass = if source.is_a?(Database) 42: c = Class.new(Model) 43: c.db = source 44: c 45: else 46: Class.new(Model).set_dataset(source) 47: end 48: Sequel.synchronize{Model::ANONYMOUS_MODEL_CLASSES[source] = klass} if Sequel::Model.cache_anonymous_models 49: klass 50: end
Returns true if the passed object could be a specifier of conditions, false otherwise. Currently, Sequel considers hashes and arrays of two element arrays as condition specifiers.
Sequel.condition_specifier?({}) # => true Sequel.condition_specifier?([[1, 2]]) # => true Sequel.condition_specifier?([]) # => false Sequel.condition_specifier?([1]) # => false Sequel.condition_specifier?(1) # => false
# File lib/sequel/core.rb, line 117 117: def self.condition_specifier?(obj) 118: case obj 119: when Hash 120: true 121: when Array 122: !obj.empty? && !obj.is_a?(SQL::ValueList) && obj.all?{|i| (Array === i) && (i.length == 2)} 123: else 124: false 125: end 126: end
Creates a new database object based on the supplied connection string and optional arguments. The specified scheme determines the database class used, and the rest of the string specifies the connection options. For example:
DB = Sequel.connect('sqlite:/') # Memory database DB = Sequel.connect('sqlite://blog.db') # ./blog.db DB = Sequel.connect('sqlite:///blog.db') # /blog.db DB = Sequel.connect('postgres://user:password@host:port/database_name') DB = Sequel.connect('sqlite:///blog.db', :max_connections=>10)
If a block is given, it is passed the opened Database object, which is closed when the block exits. For example:
Sequel.connect('sqlite://blog.db'){|db| puts db[:users].count}
For details, see the "Connecting to a Database" guide. To set up a master/slave or sharded database connection, see the "Master/Slave Databases and Sharding" guide.
# File lib/sequel/core.rb, line 146 146: def self.connect(*args, &block) 147: Database.connect(*args, &block) 148: end
Convert the exception to the given class. The given class should be Sequel::Error or a subclass. Returns an instance of klass with the message and backtrace of exception.
# File lib/sequel/core.rb, line 159 159: def self.convert_exception_class(exception, klass) 160: return exception if exception.is_a?(klass) 161: e = klass.new("#{exception.class}: #{exception.message}") 162: e.wrapped_exception = exception 163: e.set_backtrace(exception.backtrace) 164: e 165: end
Load all Sequel extensions given. Extensions are just files that exist under sequel/extensions in the load path, and are just required. Generally, extensions modify the behavior of Database and/or Dataset, but Sequel ships with some extensions that modify other classes that exist for backwards compatibility. In some cases, requiring an extension modifies classes directly, and in others, it just loads a module that you can extend other classes with. Consult the documentation for each extension you plan on using for usage.
Sequel.extension(:schema_dumper) Sequel.extension(:pagination, :query)
# File lib/sequel/core.rb, line 177 177: def self.extension(*extensions) 178: extensions.each{|e| tsk_require "sequel/extensions/#{e}"} 179: end
Set the method to call on identifiers going into the database. This affects the literalization of identifiers by calling this method on them before they are input. Sequel upcases identifiers in all SQL strings for most databases, so to turn that off:
Sequel.identifier_input_method = nil
to downcase instead:
Sequel.identifier_input_method = :downcase
Other String instance methods work as well.
# File lib/sequel/core.rb, line 192 192: def self.identifier_input_method=(value) 193: Database.identifier_input_method = value 194: end
Set the method to call on identifiers coming out of the database. This affects the literalization of identifiers by calling this method on them when they are retrieved from the database. Sequel downcases identifiers retrieved for most databases, so to turn that off:
Sequel.identifier_output_method = nil
to upcase instead:
Sequel.identifier_output_method = :upcase
Other String instance methods work as well.
# File lib/sequel/core.rb, line 208 208: def self.identifier_output_method=(value) 209: Database.identifier_output_method = value 210: end
Yield the Inflections module if a block is given, and return the Inflections module.
# File lib/sequel/model/inflections.rb, line 4 4: def self.inflections 5: yield Inflections if block_given? 6: Inflections 7: end
Allowing loading the necessary JDBC support via a gem, which works for PostgreSQL, MySQL, and SQLite.
# File lib/sequel/adapters/jdbc.rb, line 130 130: def self.load_gem(name) 131: begin 132: Sequel.tsk_require "jdbc/#{name}" 133: rescue LoadError 134: # jdbc gem not used, hopefully the user has the .jar in their CLASSPATH 135: end 136: end
The preferred method for writing Sequel migrations, using a DSL:
Sequel.migration do up do create_table(:artists) do primary_key :id String :name end end down do drop_table(:artists) end end
Designed to be used with the Migrator class, part of the migration extension.
# File lib/sequel/extensions/migration.rb, line 272 272: def self.migration(&block) 273: MigrationDSL.create(&block) 274: end
Additional options supported:
:autoid : | Call autoid= with the value |
:columns : | Call columns= with the value |
:fetch : | Call fetch= with the value |
:numrows : | Call numrows= with the value |
:extend : | A module the object is extended with. |
:sqls : | The array to store the SQL queries in. |
# File lib/sequel/adapters/mock.rb, line 132 132: def initialize(opts={}) 133: super 134: opts = @opts 135: @sqls = opts[:sqls] || [] 136: if mod_name = SHARED_ADAPTERS[opts[:host]] 137: @shared_adapter = true 138: require "sequel/adapters/shared/#{opts[:host]}" 139: extend Sequel.const_get(mod_name)::DatabaseMethods 140: extend_datasets Sequel.const_get(mod_name)::DatasetMethods 141: if pr = SHARED_ADAPTER_SETUP[opts[:host]] 142: pr.call(self) 143: end 144: end 145: self.autoid = opts[:autoid] 146: self.columns = opts[:columns] 147: self.fetch = opts[:fetch] 148: self.numrows = opts[:numrows] 149: extend(opts[:extend]) if opts[:extend] 150: sqls 151: end
Convert each item in the array to the correct type, handling multi-dimensional arrays. For each element in the array or subarrays, call the converter, unless the value is nil.
# File lib/sequel/core.rb, line 223 223: def self.recursive_map(array, converter) 224: array.map do |i| 225: if i.is_a?(Array) 226: recursive_map(i, converter) 227: elsif i 228: converter.call(i) 229: end 230: end 231: end
Require all given files which should be in the same or a subdirectory of this file. If a subdir is given, assume all files are in that subdir. This is used to ensure that the files loaded are from the same version of Sequel as this file.
# File lib/sequel/core.rb, line 237 237: def self.require(files, subdir=nil) 238: Array(files).each{|f| super("#{File.dirname(__FILE__).untaint}/#{"#{subdir}/" if subdir}#{f}")} 239: end
Set whether Sequel is being used in single threaded mode. By default, Sequel uses a thread-safe connection pool, which isn‘t as fast as the single threaded connection pool, and also has some additional thread safety checks. If your program will only have one thread, and speed is a priority, you should set this to true:
Sequel.single_threaded = true
# File lib/sequel/core.rb, line 248 248: def self.single_threaded=(value) 249: @single_threaded = value 250: Database.single_threaded = value 251: end
Splits the symbol into three parts. Each part will either be a string or nil.
For columns, these parts are the table, column, and alias. For tables, these parts are the schema, table, and alias.
# File lib/sequel/core.rb, line 262 262: def self.split_symbol(sym) 263: case s = sym.to_s 264: when COLUMN_REF_RE1 265: [$1, $2, $3] 266: when COLUMN_REF_RE2 267: [nil, $1, $2] 268: when COLUMN_REF_RE3 269: [$1, $2, nil] 270: else 271: [nil, s, nil] 272: end 273: end
Converts the given string into a Date object.
Sequel.string_to_date('2010-09-10') # Date.civil(2010, 09, 10)
# File lib/sequel/core.rb, line 278 278: def self.string_to_date(string) 279: begin 280: Date.parse(string, Sequel.convert_two_digit_years) 281: rescue => e 282: raise convert_exception_class(e, InvalidValue) 283: end 284: end
Converts the given string into a Time or DateTime object, depending on the value of Sequel.datetime_class.
Sequel.string_to_datetime('2010-09-10 10:20:30') # Time.local(2010, 09, 10, 10, 20, 30)
# File lib/sequel/core.rb, line 290 290: def self.string_to_datetime(string) 291: begin 292: if datetime_class == DateTime 293: DateTime.parse(string, convert_two_digit_years) 294: else 295: datetime_class.parse(string) 296: end 297: rescue => e 298: raise convert_exception_class(e, InvalidValue) 299: end 300: end
Converts the given string into a Sequel::SQLTime object.
v = Sequel.string_to_time('10:20:30') # Sequel::SQLTime.parse('10:20:30') DB.literal(v) # => '10:20:30'
# File lib/sequel/core.rb, line 306 306: def self.string_to_time(string) 307: begin 308: SQLTime.parse(string) 309: rescue => e 310: raise convert_exception_class(e, InvalidValue) 311: end 312: end
Yield directly to the block. You don‘t need to synchronize access on MRI because the GVL makes certain methods atomic.
# File lib/sequel/core.rb, line 327 327: def self.synchronize(&block) 328: yield 329: end
Unless in single threaded mode, protects access to any mutable global data structure in Sequel. Uses a non-reentrant mutex, so calling code should be careful.
# File lib/sequel/core.rb, line 321 321: def self.synchronize(&block) 322: @single_threaded ? yield : @data_mutex.synchronize(&block) 323: end
Uses a transaction on all given databases with the given options. This:
Sequel.transaction([DB1, DB2, DB3]){...}
is equivalent to:
DB1.transaction do DB2.transaction do DB3.transaction do ... end end end
except that if Sequel::Rollback is raised by the block, the transaction is rolled back on all databases instead of just the last one.
Note that this method cannot guarantee that all databases will commit or rollback. For example, if DB3 commits but attempting to commit on DB2 fails (maybe because foreign key checks are deferred), there is no way to uncommit the changes on DB3. For that kind of support, you need to have two-phase commit/prepared transactions (which Sequel supports on some databases).
# File lib/sequel/core.rb, line 355 355: def self.transaction(dbs, opts={}, &block) 356: unless opts[:rollback] 357: rescue_rollback = true 358: opts = opts.merge(:rollback=>:reraise) 359: end 360: pr = dbs.reverse.inject(block){|bl, db| proc{db.transaction(opts, &bl)}} 361: if rescue_rollback 362: begin 363: pr.call 364: rescue Sequel::Rollback => e 365: nil 366: end 367: else 368: pr.call 369: end 370: end
Same as Sequel.require, but wrapped in a mutex in order to be thread safe.
# File lib/sequel/core.rb, line 373 373: def self.ts_require(*args) 374: check_requiring_thread{require(*args)} 375: end
Same as Kernel.require, but wrapped in a mutex in order to be thread safe.
# File lib/sequel/core.rb, line 378 378: def self.tsk_require(*args) 379: check_requiring_thread{k_require(*args)} 380: end
Modify the type translator for the date type depending on the value given.
# File lib/sequel/adapters/utils/pg_types.rb, line 75 75: def self.use_iso_date_format=(v) 76: PG_TYPES[1082] = v ? TYPE_TRANSLATOR.method(:date) : Sequel.method(:string_to_date) 77: @use_iso_date_format = v 78: end
If the supplied block takes a single argument, yield a new SQL::VirtualRow instance to the block argument. Otherwise, evaluate the block in the context of a new SQL::VirtualRow instance.
Sequel.virtual_row{a} # Sequel::SQL::Identifier.new(:a) Sequel.virtual_row{|o| o.a{}} # Sequel::SQL::Function.new(:a)
# File lib/sequel/core.rb, line 389 389: def self.virtual_row(&block) 390: vr = SQL::VirtualRow.new 391: case block.arity 392: when -1, 0 393: vr.instance_eval(&block) 394: else 395: block.call(vr) 396: end 397: end
Return a related Connection option connecting to the given shard.
# File lib/sequel/adapters/mock.rb, line 154 154: def connect(server) 155: Connection.new(self, server, server_opts(server)) 156: end
Store the sql used for later retrieval with sqls, and return the appropriate value using either the autoid, fetch, or numrows methods.
# File lib/sequel/adapters/mock.rb, line 161 161: def execute(sql, opts={}, &block) 162: synchronize(opts[:server]){|c| _execute(c, sql, opts, &block)} 163: end
Store the sql used, and return the value of the numrows method.
# File lib/sequel/adapters/mock.rb, line 167 167: def execute_dui(sql, opts={}) 168: execute(sql, opts.merge(:meth=>:numrows)) 169: end
Store the sql used, and return the value of the autoid method.
# File lib/sequel/adapters/mock.rb, line 172 172: def execute_insert(sql, opts={}) 173: execute(sql, opts.merge(:meth=>:autoid)) 174: end