Struct MeasurementSchema 

pub struct MeasurementSchema { /* private fields */ }

Schema for a single measurement (table).

Contains an ordered list of column definitions. The first column is always the timestamp. Tags and fields follow. Columns are private to preserve invariants — use add_tag() and add_field() for modification.

Implementations

impl MeasurementSchema

pub fn new(measurement: impl Into<String>) -> Self

Create a new schema with just the timestamp column.

pub fn measurement(&self) -> &str

Returns the measurement name.

pub fn columns(&self) -> &[ColumnDef]

Returns the column definitions (timestamp first, then tags, then fields).

pub fn add_tag(&mut self, name: &str) -> bool

Add a tag column if it doesn’t already exist.

Returns true if the tag was newly added, false if it already exists as a tag. Logs a warning if the name conflicts with an existing field column.

pub fn add_field( &mut self, name: &str, field_value: &FieldValue, ) -> Result<bool, SchemaError>

Add a field column if it doesn’t already exist.

Errors

Returns SchemaError::TypeConflict if the field already exists with a different type.

pub fn declare_field( &mut self, name: &str, column_type: ColumnType, ) -> Result<bool, SchemaError>

Add a field column with an explicit type.

The type-first form of add_field: it is how a decimal column gets the scale it needs before the first value arrives, and how a batch that introduces a decimal field creates the column at the widest scale the batch carries rather than at whatever scale the first point happened to have.

Returns true if the column was newly added, false if it already existed with exactly this type.

Errors

SchemaError::TypeConflict if the name already exists as a tag or with a different type — including a decimal with a different scale, which is a different type.

pub fn column(&self, name: &str) -> Option<&ColumnDef>

Look up a column by name — O(1) via the column index.

pub fn push_column(&mut self, col: ColumnDef)

Push a pre-built column definition (e.g. during WAL replay).

Silently ignores duplicates.

pub fn tag_count(&self) -> usize

Returns the number of tag columns.

pub fn field_count(&self) -> usize

Returns the number of field columns.

pub fn tag_names(&self) -> Vec<&str>

Returns the names of all tag columns.

pub fn field_names(&self) -> Vec<&str>

Returns the names of all field columns.

Trait Implementations

impl Clone for MeasurementSchema

fn clone(&self) -> MeasurementSchema

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MeasurementSchema

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for MeasurementSchema

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for MeasurementSchema

impl PartialEq for MeasurementSchema

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for MeasurementSchema

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

where __S: Serializer,

Serialize this value into the given Serde serializer.