MongoDB (standard.mongodb)

Concept Mapping

UQAL	MongoDB
Table	Collection
Row	Document
Field	Field
get_table	find()
get_row	findOne()
get_value	findOne() with projection
insert_row	insertOne()
update	updateOne() with $set
delete	deleteOne()
create_view	Aggregation pipeline
Native escape	db.mongo("…")

Connection Setup

# Local or self-hosted
uqal add-connection mydb standard.mongodb \
    --host localhost \
    --port 27017 \
    --database mydb \
    --secret user myuser \
    --secret password mypassword \
    --no-interactive

# MongoDB Atlas (connection string)
uqal add-connection atlasdb standard.mongodb \
    --option connection_string "mongodb+srv://user:password@cluster.mongodb.net/mydb" \
    --no-interactive

Options available in uqal_config.json:

Key	Default	Description
host	localhost	MongoDB host
port	27017	MongoDB port
database	—	Database name
options.connection_string	—	Full connection string (overrides host/port)
options.connect_timeout	10	Connection timeout in seconds

Type Mapping

UQAL Core Type	MongoDB BSON Type
int	Int32 / Int64
float	Double
varchar	String
bool	Boolean
date	Date
datetime	Date
json	Object
uuid	String (UUID format)

Schema Discovery: Strict vs. Flexible Collections

MongoDB collections are schema-less by default. UQAL handles this in two ways:

Strict collections — the collection has a $jsonSchema validator defined in MongoDB. UQAL reads the validator and uses it as the schema. These collections behave like typed tables.

Flexible collections — no validator defined. UQAL samples a configurable number of documents and aggregates all field names found. The result is a best-effort schema for REPL completion and type checking.

The flexible flag in the schema store marks a collection as flexible. You can force a collection to be treated as flexible even if it has a validator:

{
  "options": {
    "flexible_collections": ["logs", "events"]
  }
}

Views

create_view translates to a MongoDB aggregation pipeline with $lookup and $unwind for cross-collection queries:

mydb.create_view order_with_customer:
    let o = table orders
    let c = table customers where c.id = o.customer_id
    return o.id, o.total, c.name

Generates an aggregation pipeline stored as a MongoDB view.

Native MongoDB Queries

Pass a raw MongoDB filter document:

mydb.mongo("{ active: true, total: { $gt: 100 } }")

Blocked patterns (security validator):

• $where (JavaScript execution)
• $function (BSON function expressions)
• mapReduce (arbitrary JS)
• eval command

Example

# Connect
uqal add-connection shopdb standard.mongodb --host localhost --database shop

# Sync schema
uqal run "shopdb.sync_schema"

# Query with filter and field selection
uqal run "shopdb.orders.get_table(where status = 'open', fields id, customer, total)"

# Insert a document
uqal run "shopdb.orders.insert_row(customer = 'Alice', total = 149.90, status = 'open')"

# Native query — orders over 500 with specific fields
uqal run "shopdb.mongo('{ total: { \$gt: 500 } }')"