Schema#

Catalog rows and declarations, importable from agensgraph. The methods that return and take them are on Connection.

Catalog rows#

See Inspecting a graph.

class agensgraph.Graph(name: str, schema: str, labels: int)#

A graph.

name: str#

schema: str#: the schema it is stored in

labels: int#: how many labels it has, built-ins included

class agensgraph.LabelInfo(id: int, name: str, kind: str, parent: str | None)#

A label. Prints as Label.

id: int#: the label’s id, the first number of its elements’ identities

name: str#: as stored

kind: str#: 'v' or 'e'

parent: str | None#: the label it inherits from

property is_vertex: bool#

property is_edge: bool#

property is_builtin: bool#: ag_vertex or ag_edge.

class agensgraph.DeclaredProperty( label: str, name: str, type: str, nullable: bool, inherited: bool = False, )#

A property kept in a column of its own.

label: str#

name: str#

type: str#: the server’s spelling of its type

nullable: bool#

inherited: bool#: whether it comes from the label’s parent

class agensgraph.Index(label: str, name: str, unique: bool, definition: str)#

A property index.

label: str#

name: str#

unique: bool#

definition: str#: the statement that would create it again

class agensgraph.Constraint(label: str, name: str, unique: bool, definition: str)#

A uniqueness or check constraint.

label: str#

name: str#

unique: bool#: true for a uniqueness constraint

definition: str#: the server’s normalised rendering

class agensgraph.GraphDescription( graph: str, labels: tuple[Label, ...], properties: dict[str, tuple[PropertyShape, ...]], triples: tuple[Triple, ...], counts: dict[str, int], meta_gathered: bool, )#

What describe() returns.

graph: str#

labels: tuple[Label, ...]#: every label, as LabelInfo

properties: dict[str, tuple[PropertyShape, ...]]#: for each label but the built-ins, its properties as PropertyShapes

triples: tuple[Triple, ...]#: which labels each edge label connects

counts: dict[str, int]#: elements per label

meta_gathered: bool#: whether triples is current

class agensgraph.PropertyShape(name: str, kind: str, declared: bool)#

A property seen on a label.

name: str#

kind: str#: its JSON type, with numbers as integer or float, or a declared column’s type

declared: bool#: whether it has a column of its own

class agensgraph.Triple(start: str, edge: str, end: str, edge_count: int)#

An edge label and the labels it connects.

start: str#

edge: str#

end: str#

edge_count: int#

Declarations#

See Declaring a schema.

class agensgraph.DesiredLabel( name: str, kind: str = 'v', parent: str | None = None, properties: Sequence[PromotedProperty] = (), )#

A label that should exist.

name: str#

kind: str#: 'v' or 'e'

parent: str | None#: the label to inherit from

properties: Sequence[PromotedProperty]#: PromotedPropertys to keep in columns of their own

class agensgraph.PromotedProperty(name: str, type: str)#

A property to keep in a column of its own.

name: str#

type: str#: the column type, written into the statement as given

rendered() → str#: The column’s definition.

class agensgraph.DesiredIndex( label: str, properties: tuple[str | IndexElement, ...], unique: bool = False, name: str | None = None, method: str = 'btree', where: str | None = None, )#

A property index that should exist.

label: str#

properties: tuple[str | IndexElement, ...]#: names, or IndexElements

unique: bool#

name: str | None#: required with where

method: str#: btree, gin, hnsw, …

where: str | None#: a partial index’s predicate

property elements: tuple[IndexElement, ...]#: properties as IndexElements.

key() → tuple[str, str, tuple[IndexElement, ...]]#: What an index is matched on.

class agensgraph.IndexElement( property: str, operator_class: str | None = None, descending: bool = False, nulls_first: bool | None = None, cast: str | None = None, )#

One property of an index.

property: str#

operator_class: str | None#: only when not the default

descending: bool#

nulls_first: bool | None#: None for the default

cast: str | None#: a type to index the property as, such as vector(4)

rendered() → str#

resolved() → IndexElement#: The same with nulls_first made explicit.

nulls_come_first() → bool#

class agensgraph.Unique(label: str, property: str, name: str | None = None)#

A uniqueness constraint. Named <label>_<property>_unique without a name.

label: str#

property: str#

name: str | None#

class agensgraph.Check(label: str, expression: str, name: str)#

A check constraint over a Cypher expression. Its name is required.

label: str#

expression: str#

name: str#

Statements without a connection#

agensgraph.create_label_statement( name: str, kind: str, parent: str | None = None, properties: Sequence[PromotedProperty] = (), ) → str#: create vlabel or create elabel, if not exists.

agensgraph.create_index_statement(desired: DesiredIndex, *, if_not_exists: bool = False) → str#: create property index; with if_not_exists, which needs a name.

agensgraph.create_constraint_statement(desired: Unique | Check) → str#: create constraint. The server has no if not exists for one.