diff --git a/src/columnvalueops.rs b/src/columnvalueops.rs
new file mode 100644
index 0000000..99adf24
--- /dev/null
+++ b/src/columnvalueops.rs
@@ -0,0 +1,15 @@
+use std::borrow::Cow;
+
+pub trait ColumnValueOps: Sized {
+    fn from_string_literal(s: Cow<str>) -> Result<Self, Cow<str>>;
+    fn from_number_literal(s: Cow<str>) -> Result<Self, Cow<str>>;
+
+    /// Used for predicate logic (such as the entire WHERE expression).
+    fn tests_true(&self) -> bool;
+
+    fn equals(&self, rhs: &Self) -> Self;
+    fn not_equals(&self, rhs: &Self) -> Self;
+    fn and(&self, rhs: &Self) -> Self;
+    fn or(&self, rhs: &Self) -> Self;
+    fn concat(&self, rhs: &Self) -> Self;
+}
diff --git a/src/databaseinfo.rs b/src/databaseinfo.rs
index 09a3a87..5a991f6 100644
--- a/src/databaseinfo.rs
+++ b/src/databaseinfo.rs
@@ -1,6 +1,6 @@
+use columnvalueops::ColumnValueOps;
 use identifier::Identifier;
 use types::DbType;
-use std::borrow::Cow;
 use std::fmt;
 
 /// A read-only interface to information about the database schema.
@@ -32,17 +32,3 @@ pub trait ColumnInfo {
     fn get_name(&self) -> &Identifier;
     fn get_dbtype(&self) -> &DbType;
 }
-
-pub trait ColumnValueOps: Sized {
-    fn from_string_literal(s: Cow<str>) -> Result<Self, Cow<str>>;
-    fn from_number_literal(s: Cow<str>) -> Result<Self, Cow<str>>;
-
-    /// Used for predicate logic (such as the entire WHERE expression).
-    fn tests_true(&self) -> bool;
-
-    fn equals(&self, rhs: &Self) -> Self;
-    fn not_equals(&self, rhs: &Self) -> Self;
-    fn and(&self, rhs: &Self) -> Self;
-    fn or(&self, rhs: &Self) -> Self;
-    fn concat(&self, rhs: &Self) -> Self;
-}
diff --git a/src/queryplan/execute.rs b/src/queryplan/execute.rs
index 79864b3..aeb7084 100644
--- a/src/queryplan/execute.rs
+++ b/src/queryplan/execute.rs
@@ -1,4 +1,5 @@
-use databaseinfo::{DatabaseInfo, ColumnValueOps};
+use columnvalueops::ColumnValueOps;
+use databaseinfo::DatabaseInfo;
 use databasestorage::DatabaseStorage;
 use super::sexpression::SExpression;
 
diff --git a/src/queryplan/mod.rs b/src/queryplan/mod.rs
index afd0806..e1343c4 100644
--- a/src/queryplan/mod.rs
+++ b/src/queryplan/mod.rs
@@ -1,4 +1,5 @@
-use databaseinfo::{DatabaseInfo, TableInfo, ColumnValueOps};
+use columnvalueops::ColumnValueOps;
+use databaseinfo::{DatabaseInfo, TableInfo};
 use identifier::Identifier;
 use sqlsyntax::ast;
 
diff --git a/src/tempdb/mod.rs b/src/tempdb/mod.rs
index b70b8a8..2a577d4 100644
--- a/src/tempdb/mod.rs
+++ b/src/tempdb/mod.rs
@@ -5,11 +5,10 @@
 
 use std::borrow::Cow;
 use std::collections::BTreeSet;
-use std::fmt;
 
-use databaseinfo::{DatabaseInfo, TableInfo, ColumnInfo, ColumnValueOps};
+use databaseinfo::{DatabaseInfo, TableInfo, ColumnInfo};
 use identifier::Identifier;
-use types::DbType;
+use types::{DbType, Variant};
 use sqlsyntax::ast;
 
 mod table;
@@ -31,103 +30,9 @@ pub struct ResultSet<'a> {
 
 pub type ExecuteStatementResult<'a> = Result<ExecuteStatementResponse<'a>, String>;
 
-
-#[derive(Clone)]
-pub enum ColumnValue {
-    Null,
-    StringLiteral(String),
-    Number(u64)
-}
-
-impl fmt::Display for ColumnValue {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        match self {
-            &ColumnValue::Null => write!(f, "NULL"),
-            &ColumnValue::StringLiteral(ref s) => write!(f, "\"{}\"", s),
-            &ColumnValue::Number(n) => write!(f, "{}", n)
-        }
-    }
-}
-
-impl ColumnValue {
-    fn from_bool(value: bool) -> ColumnValue {
-        ColumnValue::Number(if value { 1 } else { 0 })
-    }
-}
-
-impl ColumnValueOps for ColumnValue {
-    fn from_string_literal(s: Cow<str>) -> Result<ColumnValue, Cow<str>> {
-        Ok(ColumnValue::StringLiteral(s.into_owned()))
-    }
-
-    fn from_number_literal(s: Cow<str>) -> Result<ColumnValue, Cow<str>> {
-        match s.parse() {
-            Ok(number) => Ok(ColumnValue::Number(number)),
-            Err(_) => Err(s)
-        }
-    }
-
-    fn tests_true(&self) -> bool {
-        match self {
-            &ColumnValue::Null => false,
-            &ColumnValue::StringLiteral(ref s) => !s.is_empty(),
-            &ColumnValue::Number(n) => n != 0
-        }
-    }
-
-    fn equals(&self, rhs: &Self) -> Self {
-        match (self, rhs) {
-            (&ColumnValue::Null, _) | (_, &ColumnValue::Null) => {
-                // NULL does not compare.
-                ColumnValue::Null
-            },
-            (&ColumnValue::StringLiteral(ref l), &ColumnValue::StringLiteral(ref r)) => {
-                ColumnValue::from_bool(l == r)
-            },
-            (&ColumnValue::Number(l), &ColumnValue::Number(r)) => {
-                ColumnValue::from_bool(l == r)
-            },
-            _ => ColumnValue::from_bool(false)
-        }
-    }
-
-    fn not_equals(&self, rhs: &Self) -> Self {
-        match (self, rhs) {
-            (&ColumnValue::Null, _) | (_, &ColumnValue::Null) => {
-                // NULL does not compare.
-                ColumnValue::Null
-            },
-            (&ColumnValue::StringLiteral(ref l), &ColumnValue::StringLiteral(ref r)) => {
-                ColumnValue::from_bool(l != r)
-            },
-            (&ColumnValue::Number(l), &ColumnValue::Number(r)) => {
-                ColumnValue::from_bool(l != r)
-            },
-            _ => ColumnValue::from_bool(true)
-        }
-    }
-
-    fn and(&self, rhs: &Self) -> Self {
-        ColumnValue::from_bool(self.tests_true() && rhs.tests_true())
-    }
-
-    fn or(&self, rhs: &Self) -> Self {
-        ColumnValue::from_bool(self.tests_true() || rhs.tests_true())
-    }
-
-    fn concat(&self, rhs: &Self) -> Self {
-        match (self, rhs) {
-            (&ColumnValue::StringLiteral(ref l), &ColumnValue::StringLiteral(ref r)) => {
-                ColumnValue::StringLiteral(format!("{}{}", l, r))
-            },
-            (e, _) => e.clone()
-        }
-    }
-}
-
 impl DatabaseInfo for TempDb {
     type Table = Table;
-    type ColumnValue = ColumnValue;
+    type ColumnValue = Variant;
 
     fn find_table_by_name(&self, name: &Identifier) -> Option<&Table> {
         self.tables.iter().find(|t| &t.name == name)
diff --git a/src/types/mod.rs b/src/types/mod.rs
index 3d2a833..0ead4b1 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -1,5 +1,8 @@
 use identifier::Identifier;
 
+mod variant;
+pub use self::variant::Variant;
+
 use std::borrow::Cow;
 
 #[derive(Debug, Copy)]
diff --git a/src/types/variant.rs b/src/types/variant.rs
new file mode 100644
index 0000000..1e434a7
--- /dev/null
+++ b/src/types/variant.rs
@@ -0,0 +1,94 @@
+use columnvalueops::ColumnValueOps;
+use std::borrow::Cow;
+use std::fmt;
+
+#[derive(Clone)]
+pub enum Variant {
+    Null,
+    StringLiteral(String),
+    Number(u64)
+}
+
+impl fmt::Display for Variant {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        match self {
+            &Variant::Null => write!(f, "NULL"),
+            &Variant::StringLiteral(ref s) => write!(f, "\"{}\"", s),
+            &Variant::Number(n) => write!(f, "{}", n)
+        }
+    }
+}
+
+fn from_bool(value: bool) -> Variant {
+    Variant::Number(if value { 1 } else { 0 })
+}
+
+impl ColumnValueOps for Variant {
+    fn from_string_literal(s: Cow<str>) -> Result<Variant, Cow<str>> {
+        Ok(Variant::StringLiteral(s.into_owned()))
+    }
+
+    fn from_number_literal(s: Cow<str>) -> Result<Variant, Cow<str>> {
+        match s.parse() {
+            Ok(number) => Ok(Variant::Number(number)),
+            Err(_) => Err(s)
+        }
+    }
+
+    fn tests_true(&self) -> bool {
+        match self {
+            &Variant::Null => false,
+            &Variant::StringLiteral(ref s) => !s.is_empty(),
+            &Variant::Number(n) => n != 0
+        }
+    }
+
+    fn equals(&self, rhs: &Self) -> Self {
+        match (self, rhs) {
+            (&Variant::Null, _) | (_, &Variant::Null) => {
+                // NULL does not compare.
+                Variant::Null
+            },
+            (&Variant::StringLiteral(ref l), &Variant::StringLiteral(ref r)) => {
+                from_bool(l == r)
+            },
+            (&Variant::Number(l), &Variant::Number(r)) => {
+                from_bool(l == r)
+            },
+            _ => from_bool(false)
+        }
+    }
+
+    fn not_equals(&self, rhs: &Self) -> Self {
+        match (self, rhs) {
+            (&Variant::Null, _) | (_, &Variant::Null) => {
+                // NULL does not compare.
+                Variant::Null
+            },
+            (&Variant::StringLiteral(ref l), &Variant::StringLiteral(ref r)) => {
+                from_bool(l != r)
+            },
+            (&Variant::Number(l), &Variant::Number(r)) => {
+                from_bool(l != r)
+            },
+            _ => from_bool(true)
+        }
+    }
+
+    fn and(&self, rhs: &Self) -> Self {
+        from_bool(self.tests_true() && rhs.tests_true())
+    }
+
+    fn or(&self, rhs: &Self) -> Self {
+        from_bool(self.tests_true() || rhs.tests_true())
+    }
+
+    fn concat(&self, rhs: &Self) -> Self {
+        match (self, rhs) {
+            (&Variant::StringLiteral(ref l), &Variant::StringLiteral(ref r)) => {
+                Variant::StringLiteral(format!("{}{}", l, r))
+            },
+            (e, _) => e.clone()
+        }
+    }
+}