clj-psql

A small wrapper around psql. Intended for use with babashka by those that don't want to maintain their own JDBC-enabled binary.

Usage

The library exposes 4 main fns:

• insert!
• query
• update!
• delete!

Each fn has two arities: one that takes in connection config and a string query and one that provides a more next.jdbc-esque interface.

Each example below assumes the following schema:

create table grades(
  name text,
  subject text,
  grade integer,
  comment text default 'N/A',
  constraint name_subject primary key(name, subject));

and the following clojure setup:

user> (require '[psql.core :as psql])
user> (def conn {:host "localhost"
                 :name "mydb"
                 :username "user"
                 :password "secret"})

insert!

Simple form

Runs the provided command and returns the number of rows inserted:

user> (psql/insert! conn "insert into grades (name, subject, grade) values ('Bobby Tables', 'Math', 100)")
1

JDBC form

Takes in table name as a keyword and a vector (or map if only inserting one row) of data. Returns the inserted rows from the database:

user> (psql/insert! conn :grades [{:name "Bobby Tables" :subject "English" :grade 72}
                                  {:name "Suzy Butterbean" :subject "Math" :grade 100}
                                  {:name "Suzy Butterbean" :subject "English" :grade 87}])
({:name "Bobby Tables",
  :subject "English",
  :grade "72",
  :comment "N/A"}
 {:name "Suzy Butterbean",
  :subject "Math",
  :grade "100",
  :comment "N/A"}
 {:name "Suzy Butterbean",
  :subject "English",
  :grade "87",
  :comment "N/A"})

query

Simple form

Runs the provided SELECT statement and parses the data into a sequence of maps:

user> (psql/query conn "select name, subject from grades where grade = 100")
({:name "Bobby Tables", :subject "Math"}
 {:name "Suzy Butterbean", :subject "Math"})

JDBC form

Takes in the table name as a keyword and a some conditions:

;; Map of conditions. All non-sequentials are assumed to be equality checks.
user> (psql/query conn :grades {:name "Bobby Tables"})
({:name "Bobby Tables",
  :subject "Math",
  :grade "100",
  :comment "N/A"}
 {:name "Bobby Tables",
  :subject "English",
  :grade "72",
  :comment "N/A"})
;; Sequentials within the conditions are assumed to be IN checks
user> (psql/query conn :grades {:grade [72 100]})
({:name "Bobby Tables",
  :subject "Math",
  :grade "100",
  :comment "N/A"}
 {:name "Bobby Tables",
  :subject "English",
  :grade "72",
  :comment "N/A"}
 {:name "Suzy Butterbean",
  :subject "Math",
  :grade "100",
  :comment "N/A"})
;; Sequentials OF maps are assumed to be discrete sets of conditions and are joined by `OR`
user> (psql/query conn :grades [{:grade [72]}
                                {:name "Suzy Butterbean" :grade 100}])
({:name "Bobby Tables",
  :subject "English",
  :grade "72",
  :comment "N/A"}
 {:name "Suzy Butterbean",
  :subject "Math",
  :grade "100",
  :comment "N/A"})

update!

Simple form

Runs the provided UPDATE statement and returns the number of rows updated:

user> (psql/update! conn "update grades set comment = 'null' where name = 'Bobby Tables'")
2

JDBC form

Takes the table name as a keyword, a map of new values to be applied to the matched rows, and some conditions. Returns the updated rows from the database:

user> (psql/update! conn :grades {:comment "moving soon"} {:name "Bobby Tables"})
({:name "Bobby Tables",
  :subject "Math",
  :grade "100",
  :comment "moving soon"}
 {:name "Bobby Tables",
  :subject "English",
  :grade "72",
  :comment "moving soon"})

delete!

Simple form

Runs the provided DELETE statement and returns the number of rows removed:

user> (psql/delete! conn "delete from grades where name = 'Bobby Tables'")
2

JDBC form

Takes the table name as a keyword and conditions. Returns the number of rows removed from the database:

user> (psql/delete! conn :grades {:subject "English"})
1 

License

Copyright © 2020 Darin Douglass

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.