8 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 [ #:log-statements? log-statements? #:max-connections max-connections #:max-idle-connections max-idle-connections]) → (-> database?) connector : (-> connection?) log-statements? : boolean? = #f max-connections : exact-positive-integer? = 16 max-idle-connections : exact-positive-integer? = 2
When the #:log-statements? argument is #t, statements are logged to the 'koyo:db-statements topic. The data part of the log message includes the thread the statement was executed from, the name of the procedure that executed the query and the statement itself.
Changed in version 0.8 of package koyo-lib: The component no longer forcefully shuts
down its associated custodian when the component is stopped. There
is now a lower bound on crypto-lib for version 1.6 to ensure
that shared libraries (eg. for libargon2) correctly get included in
distributions (using koyo dist or raco distribute).
Changed in version 0.20: Addded the #:log-statements?
argument.
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 #f '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 #f '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")))
8.1 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 #f non-empty-string?) (or/c #f (integer-in 1 65535)) (or/c non-empty-string? 'memory 'temporary) (or/c #f string?) (or/c #f 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"