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clj-jdbcutil

Clojure JDBC utility functions meant for other higher-level libraries.

Usage

On Clojars: https://clojars.org/clj-jdbcutil

Leiningen dependency: [clj-jdbcutil "0.1.0"]

Everything exists in the clj-jdbcutil.core namespace.

(ns example.app
  (:require [clj-jdbcutil.core :as ju]))

Dynamic var for database configuration keys

The dynamic var *dbspec* may be bound to a map containing well known keys and corresponding values (that users should honor):

key	type	default	description
`:datasource`	javax.sql.DataSource	`nil`
`:connection`	java.sql.Connection	`nil`
`:dbmetadata`	map	`{}`	use `dbmeta` to retrieve this value
`:catalog`	String, Keyword etc.	`nil`	SHOULD be converted using `db-iden`
`:schema`	String, Keyword etc.	`nil`	SHOULD be converted using `db-iden`
`:read-only?`	boolean	`false`	true SHOULD disallow write operations
`:show-sql?`	boolean	`true`	true SHOULD print SQL statements
`:show-sql-fn`	function (w/ 1 arg)	prints SQL using `println`	you may rebind this to fn that sends to logger
`:clj-to-db`	function (w/ 1 arg, returns string)	converts hyphen to underscore	dictates how should identifiers be converted from Clojure to the database
`:db-to-clj`	function (w/ 1 arg, returns clj form)	converts to lower-case keyword	dictates how should identifiers be converted from the database to Clojure
`:fetch-size`	Integer	1000	number of rows to fetch per DB roundtrip; helps throttle/optimize large DB reads; 0 means unlimited
`:query-timeout`	Integer	0	number of seconds to wait for query to execute, after which timeout occurs raising SqlException (not all JDBC drivers support this so check driver manual before use)

Notes:

Users MAY expose their own API to re-bind this var to new values.
Users MUST NOT alter the type/semantics of the well-defined keys.
Users MAY introduce custom keys with unique prefixes e.g. :com.foo.xlib.conn-pool-name in order to prevent name collision.

Creating datasources

You must already have the JDBC driver in the classpath. Then you can follow either of the following to create a datasource.

(make-datasource driver-classname jdbc-url)
(make-datasource driver-classname jdbc-url username password)

Note that the API above will not create a pooling datasource, and hence may not be suitable for production use. For information on how to create pooling JDBC datasources, check out clj-dbcp

Connecting

The macro with-connection can execute a body of code in the context of JDBC connection as :connection (unless already populated). This is like clojure.java.jdbc/with-connection with the exception that you must provide :datasource in the map.

(with-connection {key1 val1 key2 val2 ...}
  ...)

License

Distributed under the Eclipse Public License, the same as Clojure.