diff --git a/Cargo.toml b/Cargo.toml
index dccc6bdf1..697317c1d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -41,6 +41,7 @@ chrono = "0.4"
 derive_builder = "0.20.0"
 either = "1"
 env_logger = "0.11.0"
+fnv = "1"
 futures = "0.3"
 iceberg = { version = "0.2.0", path = "./crates/iceberg" }
 iceberg-catalog-rest = { version = "0.2.0", path = "./crates/catalog/rest" }
diff --git a/crates/iceberg/Cargo.toml b/crates/iceberg/Cargo.toml
index 32288ee81..ee6b2ff4f 100644
--- a/crates/iceberg/Cargo.toml
+++ b/crates/iceberg/Cargo.toml
@@ -40,6 +40,7 @@ bitvec = { workspace = true }
 chrono = { workspace = true }
 derive_builder = { workspace = true }
 either = { workspace = true }
+fnv = { workspace = true }
 futures = { workspace = true }
 itertools = { workspace = true }
 lazy_static = { workspace = true }
diff --git a/crates/iceberg/src/expr/mod.rs b/crates/iceberg/src/expr/mod.rs
index bbfae2003..92bb01fc2 100644
--- a/crates/iceberg/src/expr/mod.rs
+++ b/crates/iceberg/src/expr/mod.rs
@@ -118,7 +118,9 @@ impl PredicateOperator {
 
 /// Bind expression to a schema.
 pub trait Bind {
+    /// The type of the bounded result.
     type Bound;
+    /// Bind an expression to a schema.
     fn bind(self, schema: SchemaRef, case_sensitive: bool) -> crate::Result<Self::Bound>;
 }
 #[cfg(test)]
diff --git a/crates/iceberg/src/expr/predicate.rs b/crates/iceberg/src/expr/predicate.rs
index f6f1fe353..9c702fdd8 100644
--- a/crates/iceberg/src/expr/predicate.rs
+++ b/crates/iceberg/src/expr/predicate.rs
@@ -23,7 +23,8 @@ use crate::error::Result;
 use crate::expr::{Bind, BoundReference, PredicateOperator, Reference};
 use crate::spec::{Datum, SchemaRef};
 use crate::{Error, ErrorKind};
-use std::collections::HashSet;
+use fnv::FnvHashSet;
+
 use std::fmt::{Debug, Display, Formatter};
 use std::mem::MaybeUninit;
 use std::ops::Not;
@@ -167,7 +168,7 @@ pub struct SetExpression<T> {
     /// Term of this predicate, for example, `a` in `a in (1, 2, 3)`.
     term: T,
     /// Literals of this predicate, for example, `(1, 2, 3)` in `a in (1, 2, 3)`.
-    literals: HashSet<Datum>,
+    literals: FnvHashSet<Datum>,
 }
 
 impl<T: Debug> Debug for SetExpression<T> {
@@ -181,7 +182,7 @@ impl<T: Debug> Debug for SetExpression<T> {
 }
 
 impl<T> SetExpression<T> {
-    pub(crate) fn new(op: PredicateOperator, term: T, literals: HashSet<Datum>) -> Self {
+    pub(crate) fn new(op: PredicateOperator, term: T, literals: FnvHashSet<Datum>) -> Self {
         debug_assert!(op.is_set());
         Self { op, term, literals }
     }
@@ -308,7 +309,7 @@ impl Bind for Predicate {
                     .literals
                     .into_iter()
                     .map(|l| l.to(&bound_expr.term.field().field_type))
-                    .collect::<Result<HashSet<Datum>>>()?;
+                    .collect::<Result<FnvHashSet<Datum>>>()?;
 
                 match &bound_expr.op {
                     &PredicateOperator::In => {
@@ -366,7 +367,7 @@ impl Display for Predicate {
                 write!(f, "NOT ({})", expr.inputs()[0])
             }
             Predicate::Unary(expr) => {
-                write!(f, "{}", expr.term)
+                write!(f, "{} {}", expr.term, expr.op)
             }
             Predicate::Binary(expr) => {
                 write!(f, "{} {} {}", expr.term, expr.op, expr.literal)
@@ -379,7 +380,7 @@ impl Display for Predicate {
                     expr.op,
                     expr.literals
                         .iter()
-                        .map(|l| format!("{:?}", l))
+                        .map(|l| format!("{}", l))
                         .collect::<Vec<String>>()
                         .join(", ")
                 )
diff --git a/crates/iceberg/src/expr/term.rs b/crates/iceberg/src/expr/term.rs
index 12e23866f..9681e0813 100644
--- a/crates/iceberg/src/expr/term.rs
+++ b/crates/iceberg/src/expr/term.rs
@@ -17,8 +17,8 @@
 
 //! Term definition.
 
-use crate::expr::Bind;
-use crate::expr::{BinaryExpression, Predicate, PredicateOperator};
+use crate::expr::{BinaryExpression, Predicate, PredicateOperator, SetExpression};
+use crate::expr::{Bind, UnaryExpression};
 use crate::spec::{Datum, NestedField, NestedFieldRef, SchemaRef};
 use crate::{Error, ErrorKind};
 use std::fmt::{Display, Formatter};
@@ -65,6 +65,41 @@ impl Reference {
             datum,
         ))
     }
+
+    /// Creates an is null expression. For example, `a IS NULL`.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    ///
+    /// use iceberg::expr::Reference;
+    /// let expr = Reference::new("a").is_null();
+    ///
+    /// assert_eq!(&format!("{expr}"), "a IS NULL");
+    /// ```
+    pub fn is_null(self) -> Predicate {
+        Predicate::Unary(UnaryExpression::new(PredicateOperator::IsNull, self))
+    }
+
+    /// Creates an in expression. For example, `a IN (1, 2, 3)`.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    ///
+    /// use iceberg::expr::Reference;
+    /// use iceberg::spec::Datum;
+    /// let expr = Reference::new("a").r#in(vec![Datum::long(1), Datum::long(2), Datum::long(3)]);
+    ///
+    /// assert_eq!(&format!("{expr}"), "a IN (1, 3, 2)");
+    /// ```
+    pub fn r#in(self, values: impl IntoIterator<Item = Datum>) -> Predicate {
+        Predicate::Set(SetExpression::new(
+            PredicateOperator::In,
+            self,
+            values.into_iter().collect(),
+        ))
+    }
 }
 
 impl Display for Reference {
@@ -94,7 +129,7 @@ impl Bind for Reference {
 }
 
 /// A named reference in a bound expression after binding to a schema.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct BoundReference {
     // This maybe different from [`name`] filed in [`NestedField`] since this contains full path.
     // For example, if the field is `a.b.c`, then `field.name` is `c`, but `original_name` is `a.b.c`.
@@ -128,6 +163,63 @@ pub type BoundTerm = BoundReference;
 
 #[cfg(test)]
 mod tests {
+    use crate::expr::{Bind, BoundReference, Reference};
+    use crate::spec::{NestedField, PrimitiveType, Schema, SchemaRef, Type};
+    use std::sync::Arc;
+
+    fn table_schema_simple() -> SchemaRef {
+        Arc::new(
+            Schema::builder()
+                .with_schema_id(1)
+                .with_identifier_field_ids(vec![2])
+                .with_fields(vec![
+                    NestedField::optional(1, "foo", Type::Primitive(PrimitiveType::String)).into(),
+                    NestedField::required(2, "bar", Type::Primitive(PrimitiveType::Int)).into(),
+                    NestedField::optional(3, "baz", Type::Primitive(PrimitiveType::Boolean)).into(),
+                ])
+                .build()
+                .unwrap(),
+        )
+    }
+
+    #[test]
+    fn test_bind_reference() {
+        let schema = table_schema_simple();
+        let reference = Reference::new("bar").bind(schema, true).unwrap();
+
+        let expected_ref = BoundReference::new(
+            "bar",
+            NestedField::required(2, "bar", Type::Primitive(PrimitiveType::Int)).into(),
+        );
+
+        assert_eq!(expected_ref, reference);
+    }
+
     #[test]
-    fn test_bind_reference() {}
+    fn test_bind_reference_case_insensitive() {
+        let schema = table_schema_simple();
+        let reference = Reference::new("BaR").bind(schema, false).unwrap();
+
+        let expected_ref = BoundReference::new(
+            "BaR",
+            NestedField::required(2, "bar", Type::Primitive(PrimitiveType::Int)).into(),
+        );
+
+        assert_eq!(expected_ref, reference);
+    }
+
+    #[test]
+    fn test_bind_reference_failure() {
+        let schema = table_schema_simple();
+        let result = Reference::new("bar_not_eix").bind(schema, true);
+
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_bind_reference_case_insensitive_failure() {
+        let schema = table_schema_simple();
+        let result = Reference::new("BaR_non").bind(schema, false);
+        assert!(result.is_err());
+    }
 }
diff --git a/crates/iceberg/src/spec/values.rs b/crates/iceberg/src/spec/values.rs
index fe1d13457..d0730ea3c 100644
--- a/crates/iceberg/src/spec/values.rs
+++ b/crates/iceberg/src/spec/values.rs
@@ -661,7 +661,17 @@ impl Datum {
 
     /// Convert the datum to `target_type`.
     pub fn to(self, target_type: &Type) -> Result<Datum> {
-        todo!()
+        // TODO: We should allow more type conversions
+        match target_type {
+            Type::Primitive(typ) if typ == &self.r#type => Ok(self),
+            _ => Err(Error::new(
+                ErrorKind::DataInvalid,
+                format!(
+                    "Can't convert datum from {} type to {} type.",
+                    self.r#type, target_type
+                ),
+            )),
+        }
     }
 }