diff --git a/cmd/gemini/root.go b/cmd/gemini/root.go
index 6df155ee..2425b1d9 100644
--- a/cmd/gemini/root.go
+++ b/cmd/gemini/root.go
@@ -70,24 +70,29 @@ func run(cmd *cobra.Command, args []string) {
 			return
 		}
 	}
+
 	nrPassedTests := 0
 
 	for i := 0; i < maxTests; i++ {
-		mutate := schema.GenMutateOp()
+		mutateStmt := schema.GenMutateStmt()
+		mutateQuery := mutateStmt.Query
+		mutateValues := mutateStmt.Values()
 		if verbose {
-			fmt.Printf("%s\n", mutate)
+			fmt.Printf("%s (values=%v)\n", mutateQuery, mutateValues)
 		}
-		if err := session.Mutate(mutate); err != nil {
-			fmt.Printf("Failed! Mutation '%s' caused an error: '%v'\n", mutate, err)
+		if err := session.Mutate(mutateQuery, mutateValues...); err != nil {
+			fmt.Printf("Failed! Mutation '%s' (values=%v) caused an error: '%v'\n", mutateQuery, mutateValues, err)
 			return
 		}
 
-		check := schema.GenCheckOp()
+		checkStmt := schema.GenCheckStmt()
+		checkQuery := checkStmt.Query
+		checkValues := checkStmt.Values()
 		if verbose {
-			fmt.Printf("%s\n", check)
+			fmt.Printf("%s (values=%v)\n", checkQuery, checkValues)
 		}
-		if diff := session.Check(check); diff != "" {
-			fmt.Printf("Failed! Check '%s' rows differ (-oracle +test)\n%s", check, diff)
+		if diff := session.Check(checkQuery, checkValues...); diff != "" {
+			fmt.Printf("Failed! Check '%s' (values=%v) rows differ (-oracle +test)\n%s", checkQuery, checkValues, diff)
 			return
 		}
 		nrPassedTests++
diff --git a/schema.go b/schema.go
index 81faa70c..ec1d8241 100644
--- a/schema.go
+++ b/schema.go
@@ -25,8 +25,13 @@ type Table struct {
 type Schema interface {
 	GetDropSchema() []string
 	GetCreateSchema() []string
-	GenMutateOp() string
-	GenCheckOp() string
+	GenMutateStmt() *Stmt
+	GenCheckStmt() *Stmt
+}
+
+type Stmt struct {
+	Query  string
+	Values func() []interface{}
 }
 
 type schema struct {
@@ -63,25 +68,41 @@ func (s *schema) GetCreateSchema() []string {
 	}
 }
 
-func (s *schema) GenMutateOp() string {
+func (s *schema) GenMutateStmt() *Stmt {
 	columns := []string{}
 	values := []string{}
 	for _, pk := range s.table.PartitionKeys {
 		columns = append(columns, pk.Name)
-		values = append(values, fmt.Sprintf("%d", rand.Intn(100)))
+		values = append(values, "?")
 	}
 	for _, pk := range s.table.ClusteringKeys {
 		columns = append(columns, pk.Name)
-		values = append(values, fmt.Sprintf("%d", rand.Intn(100)))
+		values = append(values, "?")
 	}
 	for _, cdef := range s.table.Columns {
 		columns = append(columns, cdef.Name)
-		values = append(values, fmt.Sprintf("%d", rand.Intn(100)))
+		values = append(values, "?")
+	}
+	query := fmt.Sprintf("INSERT INTO %s.%s (%s) VALUES (%s)", s.keyspace.Name, s.table.Name, strings.Join(columns, ","), strings.Join(values, ","))
+	return &Stmt{
+		Query: query,
+		Values: func() []interface{} {
+			values := make([]interface{}, 0)
+			for _, _ = range s.table.PartitionKeys {
+				values = append(values, rand.Intn(100))
+			}
+			for _, _ = range s.table.ClusteringKeys {
+				values = append(values, rand.Intn(100))
+			}
+			for _, _ = range s.table.Columns {
+				values = append(values, rand.Intn(100))
+			}
+			return values
+		},
 	}
-	return fmt.Sprintf("INSERT INTO %s.%s (%s) VALUES (%s)", s.keyspace.Name, s.table.Name, strings.Join(columns, ","), strings.Join(values, ","))
 }
 
-func (s *schema) GenCheckOp() string {
+func (s *schema) GenCheckStmt() *Stmt {
 	query := fmt.Sprintf("SELECT * FROM %s.%s", s.keyspace.Name, s.table.Name)
 	if rand.Intn(2) == 1 {
 		query += fmt.Sprintf(" ORDER BY %s", s.table.Columns[0].Name)
@@ -92,7 +113,13 @@ func (s *schema) GenCheckOp() string {
 	if rand.Intn(2) == 1 {
 		query += fmt.Sprintf(" LIMIT %d", rand.Intn(100))
 	}
-	return query
+	values := func() []interface{} {
+		return nil
+	}
+	return &Stmt{
+		Query:  query,
+		Values: values,
+	}
 }
 
 type SchemaBuilder interface {
diff --git a/session.go b/session.go
index 23aeea8a..c2bd06ca 100644
--- a/session.go
+++ b/session.go
@@ -40,19 +40,19 @@ func (s *Session) Close() {
 	s.oracleSession.Close()
 }
 
-func (s *Session) Mutate(query string) error {
-	if err := s.testSession.Query(query).Exec(); err != nil {
+func (s *Session) Mutate(query string, values ...interface{}) error {
+	if err := s.testSession.Query(query, values...).Exec(); err != nil {
 		return fmt.Errorf("%v [cluster = test, query = '%s']", err, query)
 	}
-	if err := s.oracleSession.Query(query).Exec(); err != nil {
+	if err := s.oracleSession.Query(query, values...).Exec(); err != nil {
 		return fmt.Errorf("%v [cluster = oracle, query = '%s']", err, query)
 	}
 	return nil
 }
 
-func (s *Session) Check(query string) string {
-	testIter := s.testSession.Query(query).Iter()
-	oracleIter := s.oracleSession.Query(query).Iter()
+func (s *Session) Check(query string, values ...interface{}) string {
+	testIter := s.testSession.Query(query, values...).Iter()
+	oracleIter := s.oracleSession.Query(query, values...).Iter()
 	for {
 		testRow := make(map[string]interface{})
 		if !testIter.MapScan(testRow) {