diff --git a/src/jvmMain/kotlin/ru/landgrafhomyak/db/jdbc_kotlin_extensions/extensions.kt b/src/jvmMain/kotlin/ru/landgrafhomyak/db/jdbc_kotlin_extensions/extensions.kt
index ba9ef0b..adf9129 100644
--- a/src/jvmMain/kotlin/ru/landgrafhomyak/db/jdbc_kotlin_extensions/extensions.kt
+++ b/src/jvmMain/kotlin/ru/landgrafhomyak/db/jdbc_kotlin_extensions/extensions.kt
@@ -4,12 +4,15 @@
 
 package ru.landgrafhomyak.db.jdbc_kotlin_extensions
 
+import org.intellij.lang.annotations.Language
 import java.sql.Connection
 import java.sql.PreparedStatement
+import java.sql.ResultSet
 import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 
-public fun <R> Connection.mapQuery(sql: String, action: PreparedStatementPrepareAndFetch<R>, to: MutableList<R>) {
+public fun <R, C : MutableCollection<R>> Connection.mapQuery(sql: String, action: PreparedStatementPrepareAndFetch<R>, to: C): C {
 	this.prepareStatement(sql).use { ps ->
 		action.prepare(ps)
 		ps.executeQuery().use { rs ->
@@ -18,6 +21,7 @@ public fun <R> Connection.mapQuery(sql: String, action: PreparedStatementPrepare
 			}
 		}
 	}
+	return to
 }
 
 public fun <R> Connection.mapQuery(sql: String, action: PreparedStatementPrepareAndFetch<R>): List<R> {
@@ -28,7 +32,7 @@ public fun <R> Connection.mapQuery(sql: String, action: PreparedStatementPrepare
 
 public inline fun <R> Connection.transaction(t: (Connection) -> R): R {
 	contract {
-		callsInPlace(t)
+		callsInPlace(t, InvocationKind.EXACTLY_ONCE)
 	}
 
 	this.prepareStatement("BEGIN TRANSACTION").use { ps -> ps.executeUpdate() }
@@ -48,9 +52,32 @@ public inline fun <R> Connection.transaction(t: (Connection) -> R): R {
 }
 
 
-public inline fun <R> Connection.prepareStatement(sql: String, action: (PreparedStatement) -> R): R {
+public inline fun <R> Connection.prepareStatement(@Language("SQL") sql: String, action: (PreparedStatement) -> R): R {
 	contract {
-		callsInPlace(action)
+		callsInPlace(action, InvocationKind.EXACTLY_ONCE)
 	}
-	this.prepareStatement(sql).use { ps -> return action(ps) }
+	this.prepareStatement(sql/*.trim(' ', '\n', '\t')*/).use { ps -> return action(ps) }
+}
+
+public inline fun <R, C : MutableCollection<R>> ResultSet.mapTo(to: C, transform: (rs: ResultSet) -> R): C {
+	while (this.next()) {
+		to.add(transform(this))
+	}
+	return to
+}
+
+public inline fun <R> ResultSet.map(transform: (rs: ResultSet) -> R): List<R> =
+	this.mapTo(ArrayList(), transform)
+
+public inline fun <R, C : MutableCollection<R>> ResultSet.mapToThenClose(to: C, transform: (rs: ResultSet) -> R): C =
+	this.use { rs -> rs.mapTo(to, transform) }
+
+public inline fun <R> ResultSet.mapThenClose(transform: (rs: ResultSet) -> R): List<R> =
+	this.use { rs -> rs.map(transform) }
+
+public inline fun <R> PreparedStatement.executeQuery(action: (ResultSet) -> R): R {
+	contract {
+		callsInPlace(action, InvocationKind.EXACTLY_ONCE)
+	}
+	return this.executeQuery().use(action)
 }
\ No newline at end of file