To understand how to write internal DSLs in Scala I started implementing a small subset of the SQL language.
Implemented:
- select operation with fields
- where clause with (typed) equals, in, and, or
- order
- A ‘renderer’ to create a SQL String from the given Query object
Scala SQL DSL lets you write stuff like:
scala> val q = select ("*") from ("user") where (("name","peter") and (("active", true) or ("role", "admin")))
scala> q.sql
res0: java.lang.String = select * from user where (name = 'peter' and (active = true or role = 'admin'))
- buildr 1.4.0
- scala 2.8.0.r19281-b20091026023411 (should work with more recent versions as well)
The spec contains various examples on how to write queries. But basically you start by:
- Import all functions/implicits in the QueryBuilder object: import QueryBuilder._
- Import the AnsiSqlRenderer object: AnsiSqlRenderer._
Written by Peter Maas
This software is licensed under the Apache 2 license, quoted below.
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