graflo.db.conn¶
Abstract database connection interface for graph databases.
This module defines the abstract interface for database connections, providing a unified API for different graph database implementations. It includes methods for database management, graph structure operations, and data manipulation.
Key Components:
- Connection: Abstract base class for database connections
- ConnectionType: Type variable for connection implementations
The connection interface supports:
- Database/Graph creation and deletion
- Graph structure management (vertex types, edge types)
- Index definition
- Document operations (insert, update, fetch)
- Edge operations
- Aggregation queries
Database Organization Terminology
Different databases organize graph data differently:
-
ArangoDB:
- Database: Top-level container (like a schema)
- Collections (ArangoDB-specific): Container for vertices (vertex collections)
- Edge Collections (ArangoDB-specific): Container for edges
- Graph: Named graph that connects vertex and edge collections
-
Neo4j:
- Database: Top-level container
- Labels: Categories for nodes (equivalent to vertex types)
- Relationship Types: Types of relationships (equivalent to edge types)
- No explicit "graph" concept - all nodes/relationships are in the database
-
TigerGraph:
- Graph: Top-level container (functions like a database in ArangoDB)
- Vertex Types: Global vertex type definitions (can be shared across graphs)
- Edge Types: Global edge type definitions (can be shared across graphs)
- Vertex and edge types are associated with graphs
When using the Connection interface, the terms "vertex type" and "edge type" are used generically to refer to the appropriate concept in each database.
Example
class MyConnection(Connection): ... def create_database(self, name: str): ... # Implementation ... def execute(self, query, **kwargs): ... # Implementation
Connection
¶
Bases: ABC
Abstract base class for database connections.
This class defines the interface that all database connection implementations must follow. It provides methods for database/graph operations, graph structure management (vertex types, edge types), and data manipulation.
Note
All methods marked with @abc.abstractmethod must be implemented by
concrete connection classes. Subclasses must set the class attribute
flavor to their DBType.
Source code in graflo/db/conn.py
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__init__()
¶
aggregate(class_name, aggregation_function, discriminant=None, aggregated_field=None, filters=None)
abstractmethod
¶
Perform aggregation on a collection.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
class_name
|
str
|
Name of the collection |
required |
aggregation_function
|
AggregationType
|
Type of aggregation to perform |
required |
discriminant
|
str | None
|
Field to group by |
None
|
aggregated_field
|
str | None
|
Field to aggregate |
None
|
filters
|
list[Any] | dict[str, Any] | None
|
Query filters |
None
|
Returns:
| Type | Description |
|---|---|
int | float | list[dict[str, Any]] | dict[str, int | float] | None
|
Aggregation results (type depends on aggregation function) |
Source code in graflo/db/conn.py
clear_data(schema)
abstractmethod
¶
Remove all data from the graph without dropping or changing the schema.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
schema
|
Schema
|
Schema describing the graph (used to identify collections/labels). |
required |
close()
abstractmethod
¶
create_database(name)
abstractmethod
¶
Create a new database.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
name
|
str
|
Name of the database to create |
required |
define_edge_classes(edges)
¶
Define edge classes based on edge configurations.
This method is called from define_schema() to create edge types/collections.
Default implementation is a no-op. Override in subclasses as needed.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
edges
|
list[Edge]
|
List of edge configurations to create |
required |
Source code in graflo/db/conn.py
define_edge_indices(edges)
abstractmethod
¶
Define indices for edge classes.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
edges
|
list[Edge]
|
List of edge configurations containing index definitions |
required |
define_indexes(schema)
¶
Define indexes for vertices and edges in the schema.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
schema
|
Schema
|
Schema containing vertex and edge configurations |
required |
Source code in graflo/db/conn.py
define_schema(schema)
abstractmethod
¶
Define vertex and edge classes based on the schema.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
schema
|
Schema
|
Schema containing vertex and edge class definitions |
required |
define_vertex_classes(schema)
¶
Define vertex classes based on schema.
This method is called from define_schema() to create vertex types/collections. Most implementations take a Schema. Some implementations (like TigerGraph) may override with a more specific signature (VertexConfig).
Default implementation is a no-op. Override in subclasses as needed.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
schema
|
Schema
|
Schema containing vertex definitions |
required |
Source code in graflo/db/conn.py
define_vertex_indices(vertex_config)
abstractmethod
¶
Define indices for vertex classes.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
vertex_config
|
VertexConfig
|
Vertex configuration containing index definitions |
required |
delete_database(name)
abstractmethod
¶
Delete a database.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
name
|
str
|
Name of the database to delete |
required |
delete_graph_structure(vertex_types=(), graph_names=(), delete_all=False)
abstractmethod
¶
Delete graph structure (graphs, vertex types, edge types) from the database.
This method deletes graphs and their associated vertex/edge types. The exact behavior depends on the database implementation:
- ArangoDB: Deletes graphs and collections (vertex/edge collections)
- Neo4j: Deletes nodes from labels (vertex types) and relationships
- TigerGraph: Deletes graphs, vertex types, edge types, and jobs
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
vertex_types
|
tuple[str, ...] | list[str]
|
Vertex type names to delete (database-specific interpretation) |
()
|
graph_names
|
tuple[str, ...] | list[str]
|
Graph/database names to delete |
()
|
delete_all
|
bool
|
If True, delete all graphs and their associated structures |
False
|
Source code in graflo/db/conn.py
execute(query, **kwargs)
abstractmethod
¶
Execute a database query.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
query
|
str | Any
|
Query to execute |
required |
**kwargs
|
Any
|
Additional query parameters |
{}
|
Returns:
| Type | Description |
|---|---|
Any
|
Query result (database-specific) |
Source code in graflo/db/conn.py
expression_flavor()
classmethod
¶
Expression flavor for filter rendering (AQL, CYPHER, GSQL).
Graph connection subclasses must set class attribute flavor to a
DBType present in DB_TYPE_TO_EXPRESSION_FLAVOR.
Source code in graflo/db/conn.py
fetch_docs(class_name, filters=None, limit=None, return_keys=None, unset_keys=None, **kwargs)
abstractmethod
¶
Fetch documents from a vertex type.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
class_name
|
str
|
Name of the vertex type (or collection/label in database-specific terms) |
required |
filters
|
list[Any] | dict[str, Any] | None
|
Query filters |
None
|
limit
|
int | None
|
Maximum number of documents to return |
None
|
return_keys
|
list[str] | None
|
Keys to return |
None
|
unset_keys
|
list[str] | None
|
Keys to unset |
None
|
**kwargs
|
Any
|
Additional database-specific parameters (e.g., field_types for TigerGraph) |
{}
|
Returns:
| Name | Type | Description |
|---|---|---|
list |
list[dict[str, Any]]
|
Fetched documents |
Source code in graflo/db/conn.py
fetch_edges(from_type, from_id, edge_type=None, to_type=None, to_id=None, filters=None, limit=None, return_keys=None, unset_keys=None, **kwargs)
abstractmethod
¶
Fetch edges from the database.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
from_type
|
str
|
Source vertex type |
required |
from_id
|
str
|
Source vertex ID (required) |
required |
edge_type
|
str | None
|
Optional edge type to filter by |
None
|
to_type
|
str | None
|
Optional target vertex type to filter by |
None
|
to_id
|
str | None
|
Optional target vertex ID to filter by |
None
|
filters
|
list[Any] | dict[str, Any] | None
|
Additional query filters |
None
|
limit
|
int | None
|
Maximum number of edges to return |
None
|
return_keys
|
list[str] | None
|
Keys to return (projection) |
None
|
unset_keys
|
list[str] | None
|
Keys to exclude (projection) |
None
|
**kwargs
|
Any
|
Additional database-specific parameters |
{}
|
Returns:
| Name | Type | Description |
|---|---|---|
list |
list[dict[str, Any]]
|
List of fetched edges |
Source code in graflo/db/conn.py
fetch_present_documents(batch, class_name, match_keys, keep_keys=None, flatten=False, filters=None)
abstractmethod
¶
Fetch documents that exist in the database.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
batch
|
list[dict[str, Any]]
|
Batch of documents to check |
required |
class_name
|
str
|
Name of the collection |
required |
match_keys
|
list[str] | tuple[str, ...]
|
Keys to match |
required |
keep_keys
|
list[str] | tuple[str, ...] | None
|
Keys to keep in result |
None
|
flatten
|
bool
|
Whether to flatten the result. If True, returns a flat list. If False, returns a dict mapping batch indices to matching documents. |
False
|
filters
|
list[Any] | dict[str, Any] | None
|
Additional query filters |
None
|
Returns:
| Type | Description |
|---|---|
list[dict[str, Any]] | dict[int, list[dict[str, Any]]]
|
list | dict: Documents that exist in the database. Returns a list if flatten=True, otherwise returns a dict mapping batch indices to documents. |
Source code in graflo/db/conn.py
init_db(schema, recreate_schema)
abstractmethod
¶
Initialize the database with the given schema.
If the schema/graph already exists and recreate_schema is False, raises SchemaExistsError and the script halts.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
schema
|
Schema
|
Schema to initialize the database with |
required |
recreate_schema
|
bool
|
If True, drop existing schema and define new one. If False and schema/graph already exists, raises SchemaExistsError. |
required |
Source code in graflo/db/conn.py
insert_edges_batch(docs_edges, source_class, target_class, relation_name, match_keys_source, match_keys_target, filter_uniques=True, head=None, **kwargs)
abstractmethod
¶
Insert a batch of edges.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
docs_edges
|
list[list[dict[str, Any]]] | list[Any] | None
|
Edge documents to insert |
required |
source_class
|
str
|
Source vertex type/class |
required |
target_class
|
str
|
Target vertex type/class |
required |
relation_name
|
str
|
Name of the edge type/relation |
required |
match_keys_source
|
tuple[str, ...]
|
Keys to match source vertices |
required |
match_keys_target
|
tuple[str, ...]
|
Keys to match target vertices |
required |
filter_uniques
|
bool
|
Whether to filter unique edges |
True
|
head
|
int | None
|
Optional limit on number of edges to insert |
None
|
**kwargs
|
Any
|
Additional insertion parameters, including: - collection_name: Name of the edge type (database-specific: collection/relationship type). Required for ArangoDB (defaults to {source_class}_{target_class}_edges if not provided), optional for other databases. - uniq_weight_fields: Fields to consider for uniqueness (ArangoDB-specific) - uniq_weight_collections: Vertex/edge types to consider for uniqueness (ArangoDB-specific) - upsert_option: Whether to upsert existing edges (ArangoDB-specific) |
{}
|
Source code in graflo/db/conn.py
insert_return_batch(docs, class_name)
abstractmethod
¶
Insert documents and return the inserted documents.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
docs
|
list[dict[str, Any]]
|
Documents to insert |
required |
class_name
|
str
|
Name of the vertex type (or collection/label in database-specific terms) |
required |
Returns:
| Type | Description |
|---|---|
list[dict[str, Any]] | str
|
list | str: Inserted documents, or a query string (database-specific behavior). Most implementations return a list of inserted documents. ArangoDB returns an AQL query string for deferred execution. |
Source code in graflo/db/conn.py
keep_absent_documents(batch, class_name, match_keys, keep_keys=None, filters=None)
abstractmethod
¶
Keep documents that don't exist in the database.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
batch
|
list[dict[str, Any]]
|
Batch of documents to check |
required |
class_name
|
str
|
Name of the collection |
required |
match_keys
|
list[str] | tuple[str, ...]
|
Keys to match |
required |
keep_keys
|
list[str] | tuple[str, ...] | None
|
Keys to keep in result |
None
|
filters
|
list[Any] | dict[str, Any] | None
|
Additional query filters |
None
|
Returns:
| Name | Type | Description |
|---|---|---|
list |
list[dict[str, Any]]
|
Documents that don't exist in the database |
Source code in graflo/db/conn.py
upsert_docs_batch(docs, class_name, match_keys, **kwargs)
abstractmethod
¶
Upsert a batch of documents.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
docs
|
list[dict[str, Any]]
|
Documents to upsert |
required |
class_name
|
str
|
Name of the vertex type (or collection/label in database-specific terms) |
required |
match_keys
|
list[str] | tuple[str, ...]
|
Keys to match for upsert |
required |
**kwargs
|
Any
|
Additional upsert parameters |
{}
|
Source code in graflo/db/conn.py
SchemaExistsError
¶
Bases: RuntimeError
Raised when schema/graph already exists and recreate_schema is False.
Set recreate_schema=True to replace the existing schema, or use clear_data=True before ingestion to only clear data without touching the schema.