Squala

A SQL DSL in Scala that generates SQL in a predictable way.

Squala is different from other SQL DSLs in that it doesn't try to be type-safe or map Scala objects to SQL tables. Instead, it tries to offer the same control as embedded SQL but without the messiness and error-proneness of string concatenation.

It was built with PostgreSQL in mind, but should work with most databases.

Squala is a work in progress, and contributions and ideas are very welcome.

Installation

This will be expanded later.

Notes

Squala is easiest to use if you import its implicits and the functions from the Squala object.

scala> import st.process.squala.SqualaImplicits._
import st.process.squala.SqualaImplicits._

scala> import st.process.squala.Squala._
import st.process.squala.Squala._

scala> (select ("*") from "foo").sql
res0: String = select * from foo

Squala can do more than just select from a table. Among other features, it supports table aliases, literals, and where clauses.

scala> (select ("*") from "foo" as "f" where ("f.bar" === 42)).sql
res1: String = select * from foo f where (f.bar = 42)

scala> (select ("*") from "users" as "u" where ("u.login_count" === 42 and "u.email_verified" === false)).sql
res2: String = select * from users u where ((u.login_count = 42) and (u.email_verified = 0))

Squala also supports joins and sub-queries:

scala> (select ("*") from "users" as "u" innerJoin ("identities", "i") on ("i.id" === "u.identity_id")).sql
res3: String = select * from users u inner join identities i on (i.id = u.identity_id)

scala> val q1 = select ("*") from "foo"
res4: st.process.squala.From = select * from foo

scala> ((select ("*") from "bar").where exists q1).sql
res5: String = select * from bar where exists (select * from foo)

Author

Cameron McKay

License

This library is available under the MIT license.