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MongoDB

Create

11 samples, from the least code that works to complete workflows.

What a create does

Rule On MongoDB
Where it goes The entity's name is the collection; MongoDB makes a collection on its first insert
The id The declared id is the document's _id, named in your code by its declared column (account_id)
A generated string id An ObjectId ARX makes before the insert, returned as its 24-character text
A generated Guid id A version 7 Guid ARX makes (new ids sort by time)
A generated number id Refused (ARX8001): MongoDB has no sequences
No id (NoIdColumn) Refused (ARX1001): every MongoDB document has an _id
A duplicate ARX3001 UniqueViolation, naming the index; a plain insert never replaces a document
Names ASCII letters, digits and _; a $ or SQL syntax is ARX1017; field names keep their case
Without a catalog Not resolved: a collection has no declared id to read, so a table the catalog (or entity.IdColumn) doesn't declare stays ARX1016 IdNotDeclared. The SQL providers resolve it (capability SchemaResolution, which MongoDB doesn't declare)

Reference

Value types

.NET value Stored as
string, char string
a plain enum refused (ARX1007): write (int)value or value.ToString(), or use a selection set
int, short, byte 32-bit integer
long, uint 64-bit integer
decimal Decimal128 (exact)
double, float double (NaN and infinity allowed)
bool boolean
Guid binary subtype 4 (UUID)
byte[], ArxBytea binary
ArxJsonB an embedded document or array (its JSON parsed)
an array or a list an array of the values above
ArxSelectionSetValue its code, or an array of codes
ArxEntityReference the referenced id, as the referenced collection stores it (an ObjectId for a generated string id)
null null

Dates and times

.NET value Stored as
DateTime (UTC) a BSON date, to the millisecond: finer ticks are dropped
DateTime (Local) converted to UTC
DateTime (Unspecified) taken as UTC
DateTimeOffset its UTC instant (the offset isn't kept)
DateOnly midnight UTC of that day
TimeOnly, TimeSpan text (09:30:00.0000000, 1.02:03:04)
default(DateTime), default(DateTimeOffset), default(DateOnly) refused (ARX1013): they mean "not set"

The samples

Basics

The least code that works.

1Create one record and get its idProgressive

The smallest create: one document, in four scenarios. The usual way first (the id declared in the schema, an ObjectId ARX makes), then the id declared on the entity, then an id you supply, then a Guid id.

2Create a record that refers to anotherProgressive

A document that refers to another: a contact of an account, in two scenarios. The reference is an ArxEntityReference made from the id CreateAsync returned; one to a collection the schema doesn't declare is refused before anything is sent.

3Catch the errors a create meetsProgressive

The errors a create meets most, in three scenarios: a duplicate (a unique index), a value ARX refuses before sending anything, and an id MongoDB can't make.

Real cases

What an application does: a small CRM and product catalogue.

1Store every kind of valueProgressive

What each .NET value becomes in MongoDB, in three scenarios: numbers, text and flags; dates and times; and the shapes a document can hold, an embedded document, an array and a picklist with several choices.

2Catch an injection attemptProgressive

A form whose fields become attributes, attacked in three ways: a field named like a MongoDB operator, a field named with SQL in it, and a value that looks like an operator.

Advanced cases

Dependency injection, transactions, batch scopes and setting the service up.

1Create in an ARX transactionAdvanced

Several calls in one ARX transaction, in two scenarios: an account and its contacts committed together, and a transaction a failed call aborts, so nothing of it is stored.

2A security check around creates: log, block, handle false positivesAdvanced

A security check around every create (SecurityGuard, in the project root), in four scenarios: a normal request passes through; an attack is logged and the user sees a plain message; repeated attacks block the user; and a false positive, a harmless file header flagged as SQL, is triaged and fixed without blocking anyone.

3Set up the service from the database's schemaAdvanced

The service set up from the database instead of by hand, in three scenarios: preload a collection at startup, create through the preloaded service, and Strict, where only the preloaded fields may be written.

4Set the service up for productionAdvanced

Set the service up for production, in three scenarios: depend on IArxDataService, check the server at startup, and trace and measure every call.

5Use fields named outside the name rule, through aliasesAdvanced

Use documents whose fields are named outside ARX's name rule, in three scenarios: declare an alias for each such field and create documents through them, read and query by the aliases, and see what is still refused: the field's own name in a call, and a field name MongoDB would read as a path.

6Log every call through ILoggerAdvanced

Log every ARX call through ILogger, in three scenarios: one line per call with its table and how long it took, a failed call with its ARX code (and the exception logged where it is caught), and only the calls worth keeping in production.