Metadata

Lambda ORM has the following methods to extract metadata information from queries.

To execute these methods it is not necessary to connect to the database.

method	Description	Path
parameters	Get parameters in the query	orm.parameters(query)
model	Get model of the result in an execution	orm.model(query)
metadata	Get metadata of the query	orm.metadata(query)
plan	Get plan in the dialect of the physical model	orm.plan(query)
constraints	Get constraints of query	orm.constraints(query)

Example:

import { orm } from 'lambdaorm'

(async () => {
try {
  await orm.init()  
    const query = (id:number) => Orders.filter(p => p.id === id).include(p => p.details).map(p => ({ name: p.orderDate, customer: p.customer.name }))

    const parameters = await orm.parameters(query)
    const model = await orm.model(query)    
    const sentences = await orm.sentence(query)
  const constraints = await orm.constraints(query)
  const plan = await orm.plan(query)

    console.log(JSON.stringify(parameters, null, 2))
    console.log(JSON.stringify(model, null, 2))
  console.log(JSON.stringify(sentences, null, 2))
  console.log(JSON.stringify(constraints, null, 2))
    console.log(JSON.stringify(plan, null, 2))
} catch (error) {
    console.log(error)
} finally {
    await orm.end()
}
})()

Results:

Parameters:

{
  "id": "integer"
}

Model:

{
  "name": "dateTime",
  "customer": "string",
  "details": [
    {
      "orderId": "integer",
      "productId": "integer",
      "unitPrice": "decimal",
      "quantity": "decimal",
      "discount": "decimal"
    }
  ]
}

Metadata:

{"n":"select","t":"Sentence","c":[{"n":"filter","t":"Filter","c":[{"n":"===","t":"Operator","c":[{"n":"id","t":"Field","c":[],"e":"Orders","m":"o.OrderID"},{"n":"id","t":"Variable","c":[],"u":1}]}]},{"n":"Orders.o","t":"From","c":[]},{"n":"map","t":"Map","c":[{"n":"obj","t":"Obj","c":[{"n":"name","t":"KeyValue","c":[{"n":"orderDate","t":"Field","c":[],"e":"Orders","m":"o.OrderDate"}]},{"n":"customer","t":"KeyValue","c":[{"n":"name","t":"Field","c":[],"e":"Customers","m":"c.CompanyName"}]},{"n":"__id","t":"KeyValue","c":[{"n":"id","t":"Field","c":[],"e":"Orders","m":"o.OrderID"}]}]}]},{"n":"details","t":"SentenceInclude","c":[{"n":"select","t":"Sentence","c":[{"n":"filter","t":"Filter","c":[{"n":"includes","t":"FunctionRef","c":[{"n":"orderId","t":"Field","c":[],"e":"OrderDetails","m":"o1.OrderID"},{"n":"__parentId","t":"Variable","c":[],"u":1}]}]},{"n":"Order Details.o1","t":"From","c":[]},{"n":"map","t":"Map","c":[{"n":"obj","t":"Obj","c":[{"n":"orderId","t":"KeyValue","c":[{"n":"orderId","t":"Field","c":[],"e":"OrderDetails","m":"o1.OrderID"}]},{"n":"productId","t":"KeyValue","c":[{"n":"productId","t":"Field","c":[],"e":"OrderDetails","m":"o1.ProductID"}]},{"n":"unitPrice","t":"KeyValue","c":[{"n":"unitPrice","t":"Field","c":[],"e":"OrderDetails","m":"o1.UnitPrice"}]},{"n":"quantity","t":"KeyValue","c":[{"n":"quantity","t":"Field","c":[],"e":"OrderDetails","m":"o1.Quantity"}]},{"n":"discount","t":"KeyValue","c":[{"n":"discount","t":"Field","c":[],"e":"OrderDetails","m":"o1.Discount"}]},{"n":"__parentId","t":"KeyValue","c":[{"n":"orderId","t":"Field","c":[],"e":"OrderDetails","m":"o1.OrderID"}]}]}]}],"f":[{"name":"orderId","type":"integer"},{"name":"productId","type":"integer"},{"name":"unitPrice","type":"decimal"},{"name":"quantity","type":"decimal"},{"name":"discount","type":"decimal"},{"name":"__parentId","type":"integer"}],"p":[{"name":"__parentId","type":"array"}],"e":"OrderDetails"}],"r":{"name":"details","type":"manyToOne","composite":true,"from":"id","entity":"OrderDetails","to":"orderId"}},{"n":"Customers.c","t":"Join","c":[{"n":"==","t":"Operator","c":[{"n":"id","t":"Field","c":[],"e":"Customers","m":"c.CustomerID"},{"n":"customerId","t":"Field","c":[],"e":"Orders","m":"o.CustomerID"}]}]}],"f":[{"name":"name","type":"dateTime"},{"name":"customer","type":"string"},{"name":"__id","type":"integer"}],"p":[{"name":"id","type":"integer"}],"e":"Orders","a":{"name":"id","mapping":"OrderID","type":"integer","autoIncrement":true}}

Plan:

SELECT o.OrderDate AS `name`, c.CompanyName AS `customer`, o.OrderID AS `__id` 
FROM Orders o 
INNER JOIN Customers c ON c.CustomerID = o.CustomerID 
WHERE o.OrderID = ? 

SELECT o1.OrderID AS `orderId`, o1.ProductID AS `productId`, o1.UnitPrice AS `unitPrice`, o1.Quantity AS `quantity`, o1.Discount AS `discount`, o1.OrderID AS `__parentId` 
FROM `Order Details` o1  
WHERE  o1.OrderID IN (?)