calasql-query_3.0.1.8.source-code.Values.scala Maven / Gradle / Ivy
package scalasql.query
import scalasql.core.{Context, DialectTypeMappers, Expr, LiveExprs, Queryable, SqlStr}
import scalasql.core.SqlStr.SqlStringSyntax
/**
* A SQL `VALUES` clause, used to treat a sequence of primitive [[T]]s as
* a [[Select]] query.
*/
class Values[Q, R](val ts: Seq[R])(
implicit val qr: Queryable.Row[Q, R],
protected val dialect: DialectTypeMappers
) extends Select.Proxy[Q, R]
with Query.DelegateQueryable[Q, Seq[R]] {
assert(ts.nonEmpty, "`Values` clause does not support empty sequence")
protected def selectToSimpleSelect() = this.subquery
val tableRef = new SubqueryRef(this)
protected def columnName(n: Int) = s"column${n + 1}"
protected override val expr: Q = qr.deconstruct(ts.head)
override protected def selectRenderer(prevContext: Context): SubqueryRef.Wrapped.Renderer =
new Values.Renderer(this)(implicitly, prevContext)
override protected def selectExprAliases(prevContext: Context) = {
qr.walkExprs(expr)
.zipWithIndex
.map { case (e, i) => (Expr.identity(e), SqlStr.raw(columnName(i))) }
}
}
object Values {
class Renderer[Q, R](v: Values[Q, R])(implicit qr: Queryable.Row[Q, R], ctx: Context)
extends SubqueryRef.Wrapped.Renderer {
def wrapRow(t: R): SqlStr = sql"(" + SqlStr.join(
qr.walkExprs(qr.deconstruct(t)).map(i => sql"$i"),
SqlStr.commaSep
) + sql")"
def render(liveExprs: LiveExprs): SqlStr = {
val rows = SqlStr.join(v.ts.map(wrapRow), SqlStr.commaSep)
sql"VALUES $rows"
}
def context = ctx
}
}