7 Database
| (require koyo/database) | package: koyo-lib |
This module provides a database component and functionality for working with database connections.
procedure
(make-database-factory connector [ #:max-connections max-connections #:max-idle-connections max-idle-connections]) → (-> database?) connector : (-> connection?) max-connections : exact-positive-integer? = 16 max-idle-connections : exact-positive-integer? = 2
procedure
(call-with-database-connection database proc) → any database : database? proc : (-> connection? any)
Nested calls to call-with-database-connection reuse the same connection.
procedure
(call-with-database-transaction database proc [ #:isolation isolation]) → any database : database? proc : (-> connection? any)
isolation :
(or/c false/c 'serializable 'repeatable-read 'read-committed 'read-uncommitted) = #f
Nested calls to call-with-database-transaction reuse the same connection and, if the database supports it, create nested transactions.
syntax
(with-database-connection [id database] e ...+)
database : database?
syntax
(with-database-transaction [id database] maybe-isolation e ...+)
maybe-isolation =
| #:isolation isolation
database : database?
isolation :
(or/c false/c 'serializable 'repeatable-read 'read-committed 'read-uncommitted)
For example, the following forms are equivalent:
(with-database-connection [c the-db] (query-value c "select 42"))
(call-with-database-connection the-db (lambda (c) (query-value c "select 42")))
7.1 Database URL
| (require koyo/database-url) | package: koyo-lib |
This module provides a function for parsing DATABASE_URL-style connection strings.
procedure
→
procedure? (or/c false/c non-empty-string?) (or/c false/c (integer-in 1 65535)) (or/c non-empty-string? 'memory 'temporary) (or/c false/c string?) (or/c false/c string?) s : string?
a function that can be used to create database connections
the database server host or #f if the scheme is sqlite
the database server port or #f if the scheme is sqlite
the database name or a filename if the scheme is sqlite
the database username or #f
the database password or #f
Examples:
> (parse-database-url "sqlite3:///:memory:") #<procedure:sqlite3-connect>
#f
#f
'memory
#f
#f
> (parse-database-url "sqlite3:///db.sqlite3") #<procedure:sqlite3-connect>
#f
#f
"db.sqlite3"
#f
#f
> (parse-database-url "sqlite3:////path/to/db.sqlite3") #<procedure:sqlite3-connect>
#f
#f
"/path/to/db.sqlite3"
#f
#f
> (parse-database-url "postgres:///example") #<procedure:postgresql-connect>
"127.0.0.1"
5432
"example"
#f
#f
> (parse-database-url "postgres://127.0.0.1:15432/example") #<procedure:postgresql-connect>
"127.0.0.1"
15432
"example"
#f
#f
> (parse-database-url "postgres://user:password@127.0.0.1:15432/example") #<procedure:postgresql-connect>
"127.0.0.1"
15432
"example"
"user"
"password"