Struct TypeGuardFieldDef 

pub struct TypeGuardFieldDef {
    pub field: String,
    pub type_expr: String,
    pub required: bool,
    pub check_expr: Option<String>,
    pub default_expr: Option<String>,
    pub value_expr: Option<String>,
}

A single field guard: type check + optional REQUIRED + optional CHECK expression.

Stored as part of the collection metadata in the catalog. The check_expr is stored as a string (the original SQL expression text) and parsed into an evaluable form at enforcement time.

Fields

field: String

Field name. Supports dot-path for nested fields (e.g., “metadata.source”).

type_expr: String

Type expression string (e.g., “STRING”, “INT|NULL”, “ARRAY”).

required: bool

Whether the field must be present and non-null on every write.

check_expr: Option<String>

Optional CHECK expression as SQL text (e.g., “amount > 0”). Stored as text, parsed at enforcement time.

default_expr: Option<String>

DEFAULT expression: injected if the field is absent on write. Does NOT overwrite a user-provided value. Example: DEFAULT 'draft', DEFAULT gen_uuid_v7(), DEFAULT now().

value_expr: Option<String>

VALUE expression: always injected, even if the field is provided. Overwrites user input — use for computed/derived fields. Example: VALUE now(), VALUE LOWER(REPLACE(title, ' ', '-')).

Trait Implementations

impl Clone for TypeGuardFieldDef

fn clone(&self) -> TypeGuardFieldDef

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TypeGuardFieldDef

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TypeGuardFieldDef

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'__msgpack_de> FromMessagePack<'__msgpack_de> for TypeGuardFieldDef

fn read<R: Read<'__msgpack_de>>(reader: &mut R) -> Result<Self, Error>

where Self: Sized,

Reads the MessagePack representation of this value from the provided reader.

impl PartialEq for TypeGuardFieldDef

fn eq(&self, other: &TypeGuardFieldDef) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for TypeGuardFieldDef

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl ToMessagePack for TypeGuardFieldDef

fn write<W: Write>(&self, writer: &mut W) -> Result<(), Error>

Writes the MessagePack representation of this value into the provided writer.

impl StructuralPartialEq for TypeGuardFieldDef