[MongoDB.local Bengaluru 2018] Just in Time Validation with JSON Schema
Download as PPTX, PDF0 likes880 views
The document discusses JSON schema validation with MongoDB, highlighting the importance of using flexible yet strict schemas for data validation in applications. It provides examples of schema constraints and the integration of complex business rules in validation checks using MongoDB's expressive query syntax. Additionally, it includes resources for further learning and demo links related to schema validation.
![#MDBlocal#MDBlocal
Document Validation (v3.2)
Use query filters to define schema constraints. E.g.,
db.createCollection("orders", {
validator: {
item: {$type: "string"},
price: {$type: "decimal"},
quantity: {$type: "int"},
color: {$in: ["red", "green", "blue"]}
}
});
(ex1 – ex4)](https://image.slidesharecdn.com/1240-justintimeschemavalidationdinesh-180425155701/85/MongoDB-local-Bengaluru-2018-Just-in-Time-Validation-with-JSON-Schema-8-320.jpg)
![#MDBlocal#MDBlocal
Good for Starter Examples
{
_id: 34556,
item: "Flannel T-shirt",
price: NumberDecimal("27.99"),
quantity: NumberLong(1),
color: "green"
}
{
_id: 34556,
total: NumberDecimal("100.00"),
VAT: NumberDecimal("0.20"),
totalWithVAT: NumberDecimal("100.20"),
lineitems: [
{ sku: "MDBTS001",
name: "Flannel T-shirt",
quantity: 2,
unit_price: NumberDecimal(”40.00") },
{ sku: "MDBTS002",
quantity: 4,
unit_price: NumberDecimal(”5.00")}]
}
More Realistic](https://image.slidesharecdn.com/1240-justintimeschemavalidationdinesh-180425155701/85/MongoDB-local-Bengaluru-2018-Just-in-Time-Validation-with-JSON-Schema-12-320.jpg)
![#MDBlocal#MDBlocal
$expr
Check that totalWithVAT == total * (1+VAT):
$expr: {
$eq: [
"$totalWithVAT",
{$multiply: [
"$total",
{$sum: [1, "$VAT"]}
]}
]
}
Let's add this as a validation rule alongside our JSON Schema validation ()](https://image.slidesharecdn.com/1240-justintimeschemavalidationdinesh-180425155701/85/MongoDB-local-Bengaluru-2018-Just-in-Time-Validation-with-JSON-Schema-17-320.jpg)
![#MDBlocal#MDBlocal
Ensure total equals sum of line items
$expr: {
$eq: [
"$total",
{$sum: {
$map: {
"input": "$lineitems",
"as": "item",
"in": {
"$multiply": [
"$$item.quantity",
"$$item.unit_price"
] } } }} ] }](https://image.slidesharecdn.com/1240-justintimeschemavalidationdinesh-180425155701/85/MongoDB-local-Bengaluru-2018-Just-in-Time-Validation-with-JSON-Schema-19-320.jpg)
[MongoDB.local Bengaluru 2018] Just in Time Validation with JSON Schema
- 1. 24TH APRIL, 2018 | BENGALURU #MDBlocal Just in Time Validation with JSON Schema
- 2. #MDBlocal Dinesh Chander Team Lead, Technical Services at MongoDB @dineshchandernsit
- 7. #MDBlocal#MDBlocal { _id: 34556, item: "Flannel T-shirt", price: NumberDecimal("27.99"), quantity: NumberInt(1) color: "green" } Simple Schema to Start
- 8. #MDBlocal#MDBlocal Document Validation (v3.2) Use query filters to define schema constraints. E.g., db.createCollection("orders", { validator: { item: {$type: "string"}, price: {$type: "decimal"}, quantity: {$type: "int"}, color: {$in: ["red", "green", "blue"]} } }); (ex1 – ex4)
- 10. #MDBlocal#MDBlocal JSON Schema (v3.6) ● JSON Schema Internet Draft-04 (IETF) ● Is becoming an industry standard ● Widely used; lots of community support (ex5)
- 11. #MDBlocal#MDBlocal (ex6 - ex8b) Let’s make our validator a little more strict
- 12. #MDBlocal#MDBlocal Good for Starter Examples { _id: 34556, item: "Flannel T-shirt", price: NumberDecimal("27.99"), quantity: NumberLong(1), color: "green" } { _id: 34556, total: NumberDecimal("100.00"), VAT: NumberDecimal("0.20"), totalWithVAT: NumberDecimal("100.20"), lineitems: [ { sku: "MDBTS001", name: "Flannel T-shirt", quantity: 2, unit_price: NumberDecimal(”40.00") }, { sku: "MDBTS002", quantity: 4, unit_price: NumberDecimal(”5.00")}] } More Realistic
- 13. #MDBlocal#MDBlocal Our New Orders Schema ● Orders must contain a lineitems array of 1 to 10 documents ● Documents embedded in lineitems have fields for: ○ sku (required) ○ name (optional) ○ unit_price (required) ○ quantity (required) ● Value of quantity must be an integer ● (Must also contain fields: total, VAT, totalWithVAT, but we'll get to that.)
- 14. #MDBlocal#MDBlocal Let's validate the line item documents (embedded in an array) (ex9 - 10b)
- 15. #MDBlocal#MDBlocal Now Let's Deal with Totals and VAT The most recent order we looked at actually contains a few errors: ● The total value should be the sum of each line item sub-total ● I.e., (2 * 40) + (4 * 5) = 100 ● The totalWithVAT value should be 100 * 1.002 = 100.2 Can we enforce that totalWithVAT and total are correct using validation?
- 16. #MDBlocal#MDBlocal Yes we can! ● MongoDB 3.6 -- more expressive query syntax ● Can express complex business rules in validations ● E.g, compute and compare multiple values at runtime
- 17. #MDBlocal#MDBlocal $expr Check that totalWithVAT == total * (1+VAT): $expr: { $eq: [ "$totalWithVAT", {$multiply: [ "$total", {$sum: [1, "$VAT"]} ]} ] } Let's add this as a validation rule alongside our JSON Schema validation ()
- 18. #MDBlocal#MDBlocal Now let's make sure the total is the sum of the line item subtotals
- 19. #MDBlocal#MDBlocal Ensure total equals sum of line items $expr: { $eq: [ "$total", {$sum: { $map: { "input": "$lineitems", "as": "item", "in": { "$multiply": [ "$$item.quantity", "$$item.unit_price" ] } } }} ] }
- 20. #MDBlocal#MDBlocal All together now (ex11 - 12c)
- 23. #MDBlocal#MDBlocal Just the right amount of validation
- 24. #MDBlocal#MDBlocal When we want it, not before
- 25. #MDBlocal#MDBlocal Learn More ● Demo - https://github.com/shannonbradshaw/jsonSchema ● MongoDB Documentation ○ Schema Validation - https://docs.mongodb.com/manual/core/schema-validation/ ○ Expressive Query Syntax - https://www.mongodb.com/blog/post/mongodb-36-json- schema-validation-expressive-query-syntax ● Free MongoDB 3.6 Online Course from MongoDB University - https://university.mongodb.com/