Struct arrow::datatypes::Schema [−][src]
pub struct Schema { /* fields omitted */ }
Expand description
Describes the meta-data of an ordered sequence of relative types.
Note that this information is only part of the meta-data and not part of the physical memory layout.
Implementations
Creates a new Schema
from a sequence of Field
values.
Example
let field_a = Field::new("a", DataType::Int64, false);
let field_b = Field::new("b", DataType::Boolean, false);
let schema = Schema::new(vec![field_a, field_b]);
Creates a new Schema
from a sequence of Field
values
and adds additional metadata in form of key value pairs.
Example
let field_a = Field::new("a", DataType::Int64, false);
let field_b = Field::new("b", DataType::Boolean, false);
let mut metadata: HashMap<String, String> = HashMap::new();
metadata.insert("row_count".to_string(), "100".to_string());
let schema = Schema::new_with_metadata(vec![field_a, field_b], metadata);
Merge schema into self if it is compatible. Struct fields will be merged recursively.
Example:
use arrow::datatypes::*;
let merged = Schema::try_merge(vec![
Schema::new(vec![
Field::new("c1", DataType::Int64, false),
Field::new("c2", DataType::Utf8, false),
]),
Schema::new(vec![
Field::new("c1", DataType::Int64, true),
Field::new("c2", DataType::Utf8, false),
Field::new("c3", DataType::Utf8, false),
]),
]).unwrap();
assert_eq!(
merged,
Schema::new(vec![
Field::new("c1", DataType::Int64, true),
Field::new("c2", DataType::Utf8, false),
Field::new("c3", DataType::Utf8, false),
]),
);
Returns an immutable reference of the vector of Field
instances.
Returns an immutable reference of a specific Field
instance selected using an
offset within the internal fields
vector.
Returns an immutable reference of a specific Field
instance selected by name.
Returns a vector of immutable references to all Field
instances selected by
the dictionary ID they use.
Find the index of the column with the given name.
Returns an immutable reference to the Map of custom metadata key-value pairs.
Look up a column by name and return a immutable reference to the column along with its index.
Check to see if self
is a superset of other
schema. Here are the comparision rules:
self
andother
should contain the same number of fields- for every field
f
inother
, the field inself
with corresponding index should be a superset off
. - self.metadata is a superset of other.metadata
In other words, any record conforms to other
should also conform to self
.
Trait Implementations
fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error> where
__D: Deserializer<'de>,
fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error> where
__D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer. Read more
type Error = ArrowError
type Error = ArrowError
The type returned in the event of a conversion error.
Performs the conversion.
Auto Trait Implementations
impl RefUnwindSafe for Schema
impl UnwindSafe for Schema
Blanket Implementations
Mutably borrows from an owned value. Read more
Compare self to key
and return true
if they are equal.