diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnDef.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnDef.kt
new file mode 100644
index 00000000..2df51d41
--- /dev/null
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnDef.kt
@@ -0,0 +1,10 @@
+package hep.dataforge.tables
+
+import hep.dataforge.meta.Meta
+import kotlin.reflect.KClass
+
+data class ColumnDef<out T : Any>(
+    override val name: String,
+    override val type: KClass<out T>,
+    override val meta: Meta
+): ColumnHeader<T>
\ No newline at end of file
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnTable.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnTable.kt
index ce7b7dae..07ea5d94 100644
--- a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnTable.kt
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnTable.kt
@@ -2,34 +2,26 @@ package hep.dataforge.tables
 
 import kotlin.reflect.KClass
 
-class ColumnTable(override val columns: Map<String, Column<*>>) :
-    Table {
-    private val rowsNum = columns.values.first().size
+/**
+ * @param C bottom type for all columns in the table
+ */
+class ColumnTable<C: Any>(override val columns: Collection<Column<C>>) : Table {
+    private val rowsNum = columns.first().size
 
     init {
-        require(columns.values.all { it.size == rowsNum }) { "All columns must be of the same size" }
+        require(columns.all { it.size == rowsNum }) { "All columns must be of the same size" }
     }
 
     override val rows: List<Row>
-        get() = (0 until rowsNum).map { VirtualRow(it) }
+        get() = (0 until rowsNum).map { VirtualRow(this, it) }
 
-    @Suppress("UNCHECKED_CAST")
     override fun <T : Any> getValue(row: Int, column: String, type: KClass<out T>): T? {
         val value = columns[column]?.get(row)
-        return when {
-            value == null -> null
-            type.isInstance(value) -> value as T
-            else -> error("Expected type is $type, but found ${value::class}")
-        }
-    }
-
-    private inner class VirtualRow(val index: Int) : Row {
-        override fun <T : Any> getValue(column: String, type: KClass<out T>): T? = getValue(index, column, type)
+        return type.cast(value)
     }
 }
 
-class ColumnTableBuilder {
-    private val columns = ArrayList<Column<*>>()
+internal class VirtualRow(val table: Table, val index: Int) : Row {
+    override fun <T : Any> getValue(column: String, type: KClass<out T>): T? = table.getValue(index, column, type)
+}
 
-    fun build() = ColumnTable(columns.associateBy { it.name })
-}
\ No newline at end of file
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnTableBuilder.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnTableBuilder.kt
new file mode 100644
index 00000000..b453c957
--- /dev/null
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ColumnTableBuilder.kt
@@ -0,0 +1,58 @@
+package hep.dataforge.tables
+
+import hep.dataforge.meta.Meta
+import kotlin.reflect.KClass
+
+class ColumnTableBuilder(val size: Int) : Table {
+    private val _columns = ArrayList<Column<*>>()
+
+    override val columns: List<Column<*>> get() = _columns
+    override val rows: List<Row> get() = (0 until size).map {
+        VirtualRow(this, it)
+    }
+
+    override fun <T : Any> getValue(row: Int, column: String, type: KClass<out T>): T? {
+        val value = columns[column]?.get(row)
+        return type.cast(value)
+    }
+
+    /**
+     * Add a fixed column to the end of the table
+     */
+    fun add(column: Column<*>) {
+        require(column.size == this.size) { "Required column size $size, but found ${column.size}" }
+        _columns.add(column)
+    }
+
+    /**
+     * Insert a column at [index]
+     */
+    fun insert(index: Int, column: Column<*>) {
+        require(column.size == this.size) { "Required column size $size, but found ${column.size}" }
+        _columns.add(index, column)
+    }
+}
+
+class MapColumn<T : Any, R : Any>(
+    val source: Column<T>,
+    override val type: KClass<out R>,
+    override val name: String,
+    override val meta: Meta = source.meta,
+    val mapper: (T?) -> R?
+) : Column<R> {
+    override val size: Int get() = source.size
+
+    override fun get(index: Int): R? = mapper(source[index])
+}
+
+class CachedMapColumn<T : Any, R : Any>(
+    val source: Column<T>,
+    override val type: KClass<out R>,
+    override val name: String,
+    override val meta: Meta = source.meta,
+    val mapper: (T?) -> R?
+) : Column<R> {
+    override val size: Int get() = source.size
+    private val values: HashMap<Int, R?> = HashMap()
+    override fun get(index: Int): R? = values.getOrPut(index) { mapper(source[index]) }
+}
\ No newline at end of file
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ListColumn.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ListColumn.kt
index a926a2ad..fc7f03ea 100644
--- a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ListColumn.kt
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/ListColumn.kt
@@ -16,9 +16,16 @@ class ListColumn<T : Any>(
     companion object {
         inline operator fun <reified T : Any> invoke(
             name: String,
-            data: List<T>,
-            noinline metaBuilder: ColumnScheme.() -> Unit
-        ): ListColumn<T> = ListColumn(name, data, T::class, ColumnScheme(metaBuilder).toMeta())
+            def: ColumnScheme,
+            data: List<T?>
+        ): ListColumn<T> = ListColumn(name, data, T::class, def.toMeta())
+
+        inline operator fun <reified T : Any> invoke(
+            name: String,
+            def: ColumnScheme,
+            size: Int,
+            dataBuilder: (Int) -> T?
+        ): ListColumn<T> = invoke(name, def, List(size, dataBuilder))
     }
 }
 
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MapRow.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MapRow.kt
index 0a78ca9e..76002e9d 100644
--- a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MapRow.kt
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MapRow.kt
@@ -3,17 +3,8 @@ package hep.dataforge.tables
 import kotlin.reflect.KClass
 
 class MapRow(val values: Map<String, Any>) : Row {
-    @Suppress("UNCHECKED_CAST")
     override fun <T : Any> getValue(column: String, type: KClass<out T>): T? {
         val value = values[column]
-        return when {
-            value == null -> null
-            type.isInstance(value) -> {
-                value as T?
-            }
-            else -> {
-                error("Expected type is $type, but found ${value::class}")
-            }
-        }
+        return type.cast(value)
     }
 }
\ No newline at end of file
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MetaQuery.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MetaQuery.kt
new file mode 100644
index 00000000..cf07a5c8
--- /dev/null
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MetaQuery.kt
@@ -0,0 +1,11 @@
+package hep.dataforge.tables
+
+import hep.dataforge.meta.scheme.Scheme
+import hep.dataforge.meta.scheme.SchemeSpec
+import hep.dataforge.meta.scheme.string
+
+class MetaQuery : Scheme() {
+    var field by string()
+
+    companion object : SchemeSpec<MetaQuery>(::MetaQuery)
+}
\ No newline at end of file
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/RowTable.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/RowTable.kt
index fbcec0b7..c640aade 100644
--- a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/RowTable.kt
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/RowTable.kt
@@ -3,24 +3,21 @@ package hep.dataforge.tables
 import hep.dataforge.meta.Meta
 import kotlin.reflect.KClass
 
-data class ColumnDef<T : Any>(val name: String, val type: KClass<T>, val meta: Meta)
 
-class RowTable<R : Row>(override val rows: List<R>, private val columnDefs: List<ColumnDef<*>>) : Table {
+class RowTable<R : Row>(override val rows: List<R>, override val header: TableHeader) : Table {
     override fun <T : Any> getValue(row: Int, column: String, type: KClass<out T>): T? =
         rows[row].getValue(column, type)
 
-    override val columns: Map<String, Column<*>>
-        get() = columnDefs.associate { it.name to VirtualColumn(it) }
+    override val columns: List<Column<*>> get() = header.map { RotTableColumn(it) }
 
-    private inner class VirtualColumn<T : Any>(val def: ColumnDef<T>) :
-        Column<T> {
-
-        override val name: String get() = def.name
-        override val type: KClass<out T> get() = def.type
-        override val meta: Meta get() = def.meta
+    private inner class RotTableColumn<T : Any>(val header: ColumnHeader<T>) : Column<T> {
+        override val name: String get() = header.name
+        override val type: KClass<out T> get() = header.type
+        override val meta: Meta get() = header.meta
         override val size: Int get() = rows.size
 
         override fun get(index: Int): T? = rows[index].getValue(name, type)
     }
+
 }
 
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/Table.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/Table.kt
index 52171625..4961f9bb 100644
--- a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/Table.kt
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/Table.kt
@@ -3,16 +3,44 @@ package hep.dataforge.tables
 import hep.dataforge.meta.Meta
 import kotlin.reflect.KClass
 
-interface Table {
-    fun <T : Any> getValue(row: Int, column: String, type: KClass<out T>): T?
-    val columns: Map<String, Column<*>>
-    val rows: List<Row>
+//TODO to be removed in 1.3.70
+@Suppress("UNCHECKED_CAST")
+internal fun <T : Any> KClass<T>.cast(value: Any?): T? {
+    return when {
+        value == null -> null
+        !isInstance(value) -> error("Expected type is $this, but found ${value::class}")
+        else -> value as T
+    }
 }
 
-interface Column<out T : Any> {
+typealias TableHeader = List<ColumnHeader<*>>
+
+
+interface Table {
+    fun <T : Any> getValue(row: Int, column: String, type: KClass<out T>): T?
+    val columns: Collection<Column<*>>
+    val header: TableHeader get() = columns.toList()
+    val rows: List<Row>
+
+    /**
+     * Apply query to a table and return lazy Flow
+     */
+    //fun find(query: Any): Flow<Row>
+}
+
+operator fun Collection<Column<*>>.get(name: String): Column<*>? = find { it.name == name }
+
+inline operator fun <reified T : Any> Table.get(row: Int, column: String): T? = getValue(row, column, T::class)
+
+interface ColumnHeader<out T : Any> {
     val name: String
     val type: KClass<out T>
     val meta: Meta
+}
+
+operator fun <T : Any> Table.get(row: Int, column: Column<T>): T? = getValue(row, column.name, column.type)
+
+interface Column<out T : Any> : ColumnHeader<T> {
     val size: Int
     operator fun get(index: Int): T?
 }
@@ -20,11 +48,14 @@ interface Column<out T : Any> {
 val Column<*>.indices get() = (0 until size)
 
 operator fun <T : Any> Column<T>.iterator() = iterator {
-    for (i in indices){
+    for (i in indices) {
         yield(get(i))
     }
 }
 
 interface Row {
     fun <T : Any> getValue(column: String, type: KClass<out T>): T?
-}
\ No newline at end of file
+}
+
+inline operator fun <reified T : Any> Row.get(column: String): T? = getValue(column, T::class)
+operator fun <T : Any> Row.get(column: Column<T>): T? = getValue(column.name, column.type)
\ No newline at end of file
diff --git a/dataforge-tables/src/jvmMain/kotlin/hep/dataforge/tables/CastColumn.kt b/dataforge-tables/src/jvmMain/kotlin/hep/dataforge/tables/CastColumn.kt
new file mode 100644
index 00000000..9b9801c8
--- /dev/null
+++ b/dataforge-tables/src/jvmMain/kotlin/hep/dataforge/tables/CastColumn.kt
@@ -0,0 +1,36 @@
+package hep.dataforge.tables
+
+import hep.dataforge.meta.Meta
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KClass
+import kotlin.reflect.KProperty
+import kotlin.reflect.full.cast
+import kotlin.reflect.full.isSubclassOf
+
+@Suppress("UNCHECKED_CAST")
+fun <T : Any> Column<*>.cast(type: KClass<T>): Column<T> {
+    return if (type.isSubclassOf(this.type)) {
+        this as Column<T>
+    } else {
+        CastColumn(this, type)
+    }
+}
+
+class CastColumn<T : Any>(val origin: Column<*>, override val type: KClass<T>) : Column<T> {
+    override val name: String get() = origin.name
+    override val meta: Meta get() = origin.meta
+    override val size: Int get() = origin.size
+
+
+    override fun get(index: Int): T? = type.cast(origin[index])
+}
+
+class ColumnProperty<T : Any>(val table: Table, val type: KClass<T>) : ReadOnlyProperty<Any?, Column<T>> {
+    override fun getValue(thisRef: Any?, property: KProperty<*>): Column<T> {
+        val name = property.name
+        return (table.columns[name] ?: error("Column with name $name not found in the table")).cast(type)
+    }
+}
+
+operator fun <T : Any> Collection<Column<*>>.get(header: ColumnHeader<T>): Column<T>? =
+    find { it.name == header.name }?.cast(header.type)
diff --git a/dataforge-tables/src/jvmMain/kotlin/hep/dataforge/tables/TableAccessor.kt b/dataforge-tables/src/jvmMain/kotlin/hep/dataforge/tables/TableAccessor.kt
deleted file mode 100644
index 21453426..00000000
--- a/dataforge-tables/src/jvmMain/kotlin/hep/dataforge/tables/TableAccessor.kt
+++ /dev/null
@@ -1,37 +0,0 @@
-package hep.dataforge.tables
-
-import hep.dataforge.meta.Meta
-import kotlin.properties.ReadOnlyProperty
-import kotlin.reflect.KClass
-import kotlin.reflect.KProperty
-import kotlin.reflect.full.cast
-import kotlin.reflect.full.isSubclassOf
-
-class TableAccessor(val table: Table) : Table by table {
-    inline fun <reified T : Any> column() = ColumnProperty(table, T::class)
-}
-
-@Suppress("UNCHECKED_CAST")
-fun <T : Any> Column<*>.cast(type: KClass<T>): Column<T> {
-    return if (type.isSubclassOf(this.type)) {
-        this as Column<T>
-    } else {
-        ColumnWrapper(this, type)
-    }
-}
-
-class ColumnWrapper<T : Any>(val column: Column<*>, override val type: KClass<T>) : Column<T> {
-    override val name: String get() = column.name
-    override val meta: Meta get() = column.meta
-    override val size: Int get() = column.size
-
-
-    override fun get(index: Int): T? = type.cast(column[index])
-}
-
-class ColumnProperty<T : Any>(val table: Table, val type: KClass<T>) : ReadOnlyProperty<Any?, Column<T>?> {
-    override fun getValue(thisRef: Any?, property: KProperty<*>): Column<T>? {
-        val name = property.name
-        return table.columns[name]?.cast(type)
-    }
-}
\ No newline at end of file