Can be set to “concurrently” to connect in parallel. Whether to automatically make the maximum number of connections when setting up the pool. The amount of seconds after which the queries are logged at :warn level Whether to include connection information in log messages (false by default) Whether to keep a reference to the database in Sequel::DATABASES (true by default) The hostname of the database server to which to connect The default size for string columns (255 by default) Whether schema should be cached for this database (true by default) These extensions are loaded after connections are made by the :preconnect option. Can be a symbol, array of symbols, or string with extensions separated by columns. The name of the database to which to connectĮxtensions to load into this Database instance. These options are shared by all adapters unless otherwise noted. Using the nnect method ¶ ↑ General connection options ¶ ↑ For any application where database access is needed for a long period of time, it’s best to store the result of nnection in a constant, as recommended above. So calling nnect multiple times (say once per request), can result in a memory leak. Note that if you do not pass a block to nnect, Sequel will automatically retain a reference to the object in the Sequel::DATABASES array. When the block returns, Sequel will disconnect the database connection. If you provide a block to the method, Sequel will create a Database object and pass it as an argument to the block. Passing a block to either method ¶ ↑īoth the nnect method and the specialized adapter methods take a block. Instead, the Sequel.jdbc would be appropriate (though as mentioned below, using nnect is recommended instead of Sequel.jdbc). If you want to connect to SQLite on JRuby using the jdbc adapter, you should not use Sequel.sqlite for example, as that uses the C-based sqlite3 gem. So if you want to connect to SQLite, for example, you can do so using the sqlite, amalgalite, and jdbc adapters. Note that using an adapter method forces the use of the specified adapter, not a database type, even though some adapters have the same name as the database type. postgres( host: 'localhost', user: 'user', password: 'password', database: 'blog') postgres( 'blog', host: 'localhost', user: 'user', password: 'password')ĭB = Sequel. So the following statements are equivalent to the previous statements. The specialized adapter method is similar to nnect with an options hash, except that it automatically populates the :adapter option and assumes the first argument is the :database option, unless the first argument is a hash. connect( adapter: 'postgres', host: 'localhost', database: 'blog', user: 'user', password: 'password')Īll of the above statements are equivalent. If you do this, you must provide the adapter to use: DB = Sequel. You can also just use an options hash without a connection string. connect( 'postgres://localhost/blog', user: 'user', password: 'password') You can also pass an additional option hash with the connection string: DB = Sequel. connect( 'postgres://localhost/blog?user=user&password=password') You can use URI query parameters to specify options: DB = Sequel. The scheme/protocol part of the URI is used to determine the adapter to use: DB = Sequel. The connect method usually takes a well-formed URI, which is parsed into connection options needed to open the database connection. This is not required, but it is the convention that most Sequel code uses. If you are only connecting to a single database, it is recommended that you store the database object in a constant named DB. The connection options needed depend on the adapter being used, though most adapters share the same basic connection options. Using the specialized adapter method (Sequel.sqlite, Sequel.postgres, etc.) There are two main ways to establish database connections: Sequel provides a powerful and flexible mechanism for connecting to databases. The Database object is used to create datasets and execute queries. All Sequel activity begins with connecting to a database, which creates a Sequel::Database object.
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