diff --git a/pkg/api/v1/database_types.go b/pkg/api/v1/database_types.go
index 12786a3..5e6ecd8 100644
--- a/pkg/api/v1/database_types.go
+++ b/pkg/api/v1/database_types.go
@@ -36,6 +36,9 @@ const (
 )
 
 // DatabaseSpec is the specification of a Postgresql Database
+// +kubebuilder:validation:XValidation:rule="!has(self.builtinLocale) || self.localeProvider == 'builtin'",message="builtinLocale is only available when localeProvider is set to `builtin`"
+// +kubebuilder:validation:XValidation:rule="!has(self.icuLocale) || self.localeProvider == 'icu'",message="icuLocale is only available when localeProvider is set to `icu`"
+// +kubebuilder:validation:XValidation:rule="!has(self.icuRules) || self.localeProvider == 'icu'",message="icuRules is only available when localeProvider is set to `icu`"
 type DatabaseSpec struct {
 	// The corresponding cluster
 	ClusterRef corev1.LocalObjectReference `json:"cluster"`
@@ -67,44 +70,56 @@ type DatabaseSpec struct {
 	Encoding string `json:"encoding,omitempty"`
 
 	// The locale (cannot be changed)
+	// Sets the default collation order and character classification in the new database.
 	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="locale is immutable"
 	// +optional
 	Locale string `json:"locale,omitempty"`
 
-	// The locale provider (cannot be changed)
-	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="locale_provider is immutable"
+	// The LOCALE_PROVIDER (cannot be changed)
+	// This option sets the locale provider for databases created in the new cluster.
+	// Available from PostgreSQL 16.
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="localeProvider is immutable"
 	// +optional
-	LocaleProvider string `json:"locale_provider,omitempty"`
+	LocaleProvider string `json:"localeProvider,omitempty"`
 
 	// The LC_COLLATE (cannot be changed)
-	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="lc_collate is immutable"
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="localeCollate is immutable"
 	// +optional
-	LcCollate string `json:"lc_collate,omitempty"`
+	LcCollate string `json:"localeCollate,omitempty"`
 
 	// The LC_CTYPE (cannot be changed)
-	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="lc_ctype is immutable"
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="localeCType is immutable"
 	// +optional
-	LcCtype string `json:"lc_ctype,omitempty"`
+	LcCtype string `json:"localeCType,omitempty"`
 
 	// The ICU_LOCALE (cannot be changed)
-	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="icu_locale is immutable"
+	// Specifies the ICU locale when the ICU provider is used.
+	// This option requires `localeProvider` to be set to `icu`.
+	// Available from PostgreSQL 15.
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="icuLocale is immutable"
 	// +optional
-	IcuLocale string `json:"icu_locale,omitempty"`
+	IcuLocale string `json:"icuLocale,omitempty"`
 
 	// The ICU_RULES (cannot be changed)
-	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="icu_rules is immutable"
+	// Specifies additional collation rules to customize the behavior of the default collation.
+	// This option requires `localeProvider` to be set to `icu`.
+	// Available from PostgreSQL 16.
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="icuRules is immutable"
 	// +optional
-	IcuRules string `json:"icu_rules,omitempty"`
+	IcuRules string `json:"icuRules,omitempty"`
 
 	// The BUILTIN_LOCALE (cannot be changed)
-	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="builtin_locale is immutable"
+	// Specifies the locale name when the builtin provider is used.
+	// This option requires `localeProvider` to be set to `builtin`.
+	// Available from PostgreSQL 17.
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="builtinLocale is immutable"
 	// +optional
-	BuiltinLocale string `json:"builtin_locale,omitempty"`
+	BuiltinLocale string `json:"builtinLocale,omitempty"`
 
 	// The COLLATION_VERSION (cannot be changed)
-	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="collation_version is immutable"
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="collationVersion is immutable"
 	// +optional
-	CollationVersion string `json:"collation_version,omitempty"`
+	CollationVersion string `json:"collationVersion,omitempty"`
 
 	// True when the database is a template
 	// +optional