sqlite - 如何在 Clojure 中访问 SQLite 数据库？

Question

(ns db-example
   (:use [clojure.contrib.sql :only (with-connection with-query-results)] )
   (:import (java.sql DriverManager)))

;; need this to load the sqlite3 driver (as a side effect of evaluating the expression)
(Class/forName "org.sqlite.JDBC")

(def +db-path+  "...")
(def +db-specs+ {:classname  "org.sqlite.JDBC",
                 :subprotocol   "sqlite",
                 :subname       +db-path+})

(def +transactions-query+ "select * from my_table")

(with-connection +db-specs+
  (with-query-results results [+transactions-query+]
    ;; results is an array of column_name -> value maps
    ))

Answer 1

您实际上必须从 with-query-results 宏中返回一些内容。因为绑定(bind)到 results 的 seq 是惰性的，所以让我们使用它:

(with-connection +db-specs+  
   (with-query-results results [+transactions-query+]  
     (doall results)))  

这是使用 clojure.contrib.sql 时的常见模式，不依赖于 SQLite JDBC 适配器。

顺便说一句，我从来不需要手动执行 (Class/forName driver-class-str)，这显然是您的 Java 习惯。驱动程序加载在 contrib.sql 的底层某处。