DB - chatsession | paotharit

abstract

Stores one row per conversation session. Groups ChatMessage rows and tracks which LLM provider and model were active at session creation time.

Table Info

Property	Value
Table Name	`chatsession`
SQLAlchemy Model	`backend/app/models/chat.py :: ChatSession`
Pydantic Schema	Inline in `backend/app/api/v1/chat.py`
Migration	`SQLModel.metadata.create_all(engine)` in `backend/app/core/database.py :: init_db()`
TimescaleDB Hypertable	No

Columns

Column	Type	Nullable	Default	Notes
`id`	`UUID`	No	`uuid.uuid4()`	Primary key
`title`	`VARCHAR`	No	`"New Conversation"`	User-editable via `PATCH /api/v1/chat/sessions/{id}`
`provider`	`VARCHAR`	No	`"ollama"`	LLM provider active when session was created
`model_name`	`VARCHAR`	No	`"minimax-m2:cloud"`	LLM model active when session was created
`created_at`	`TIMESTAMP`	No	`datetime.utcnow()`	Set at Python layer, not DB server default
`updated_at`	`TIMESTAMP`	No	`datetime.utcnow()`	Not auto-updated on row change — updated manually by service

Constraints & Indexes

Type	Columns	Notes
PRIMARY KEY	`id`	UUID v4
CASCADE DELETE	via `ChatMessage.session_id`	Deleting a session deletes all its messages — defined on `ChatMessage` FK

Entity Relationships

SQLAlchemy Model (reference snapshot)

class ChatSession(SQLModel, table=True):
    id: uuid.UUID = Field(default_factory=uuid.uuid4, primary_key=True)
    title: str = Field(default="New Conversation")
    provider: str = Field(default="ollama")
    model_name: str = Field(default="minimax-m2:cloud")
    created_at: datetime = Field(default_factory=datetime.utcnow)
    updated_at: datetime = Field(default_factory=datetime.utcnow)
    messages: List["ChatMessage"] = Relationship(
        back_populates="session",
        sa_relationship_kwargs={"cascade": "all, delete-orphan"},
    )

Service Layer

Operation	File	Notes
Create session	`backend/app/api/v1/chat.py`	`POST /chat/sessions`
List sessions	`backend/app/api/v1/chat.py`	`GET /chat/sessions`
Rename session	`backend/app/api/v1/chat.py`	`PATCH /chat/sessions/{id}` — updates `title`
Delete session	`backend/app/api/v1/chat.py`	`DELETE /chat/sessions/{id}` — cascades to messages
Fetch history	`backend/app/services/chat_history_service.py`	Returns session + ordered messages

Role	Link
Child table	DB - chatmessage
Chat API	`backend/app/api/v1/chat.py`
DevOps	DevOps - DocRAG

DB - chatsession

Table Info

Columns

Constraints & Indexes

Entity Relationships

SQLAlchemy Model (reference snapshot)

Service Layer

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