FieldFlags Enumeration

Estrusco edited this page Nov 16, 2016 · 14 revisions
Clone this wiki locally

(from the official guide)

[namespace: Serenity.Data.Mapping] - [assembly: Serenity.Data]

Serenity has a set of field flags that controls field behavior.

public enum FieldFlags
   None = 0,
   Internal = 0,
   Insertable = 1,
   Updatable = 2,
   NotNull = 4,
   PrimaryKey = 8,
   AutoIncrement = 16,
   Identity = 28,
   Foreign = 32,
   Calculated = 64,
   Reflective = 128,
   ClientSide = 256,
   NotMapped = 256,
   Trim = 512,
   Default = 515,
   Required = 519,
   TrimToEmpty = 1536,
   DenyFiltering = 2048,
   Unique = 4096

An ordinary table field has Insertable, Updatable and Trim flags set by default which corresponds to Default combination flag.

See also: SetFieldFlagsAttribute

None and Internal Flag

No flags set. Internal fields are equal to no flags set.

Insertable Flag (see InsertableAttribute)

Insertable flag controls if the field is editable in new record mode. By default, all ordinary fields are considered to be insertable.

Some fields might not be insertable in database table, e.g. identity columns shouldn't have this flags set.

When a field doesn't have this flag, it won't be editable in forms in new record mode. This is also validated in services at repository level.

Sometimes, there might be internal fields that are perfectly valid in SQL INSERT statements, but shouldn't be edited in forms. One example might be a InsertedByUserId which should be set on service level, and not by end user. If we would let end user to edit it in forms, this would be a security hole. Such fields shouldn't have Insertable flag set too.

This means field flags don't have to match database table settings.

Updatable Flag (see UpdatableAttribute)

This flag is just like Insertable flag, but controls edit record mode in forms and update operations in services. By default, all ordinary fields are considered to be updatable. Server side calculated fields (like identity) shouldn't have this flag.

NotNull Flag (see NotNullAttribute)

Use this flag to set fields as not nullable. By default, this flag is set for fields that are not nullable in database, using NotNull attribute.

When a field is not nullable, its corresponding label in forms has a red asterisk and they are required to be entered.

PrimaryKey Flag (see PrimaryKeyAttribute)

Set this for primary key fields in table. Primary key fields are selected on Key column selection mode in List and Retrieve request handlers. PrimaryKey attribute sets this flag ON.

AutoIncrement Flag (see AutoIncrementAttribute)

Set this for fields that are auto incremented on server side, e.g. identity columns, or columns using a generator.

Identity Flag (see IdentityAttribute)

Set this for fields that are auto incremented on server side, e.g. identity columns, or columns using a generator. This is also primary key.

Foreign Flag

This flag is set for foreign view fields, that are originating from other tables through a join.

It is automatically set for fields with expressions containing table aliases other than T0.

For example, if a field has an attribute like [Expression("jCountry.CountryName")] it will have this flag.

This has no relation to ForeignKey attribute

Calculated Flag

If a field has an expression involving more than one field or some mathematical operations, it will have this flag.

This could also be set for fields that are calculated on SQL server side.

Reflective Flag

This is used for an advanced form of unmapped fields, where they don't have a storage of their own in row, but reflects value of another field in a different form. For example, a field that displays absolute value of a integer field that can be negative.

This should only be used in rare cases for such unmapped fields.

ClientSide Flag (see ClientSideAttribute)

OBSOLETE: Use NotMapped instead.

Corresponds to an unmapped field in Serenity entities. They don't have a corresponding field in database table.

These kinds of fields can be used for temporary calculation, storage and transfer on client and service layers.

NotMapped Flag (see NotMappedAttribute)

Property which is not mapped to a SQL field / expression.

Trim Flag

This flag is only meaningful for string typed fields and controls whether their value should be trimmed before save. All string fields have this flag on by default.

When a field value is empty string or whitespace only, it is trimmed to null.

Default Flag

These are default flags unless specified otherwise. Insertable, updatable and nullable and trimmed (to null).

Required Flag

This is a combination of Default and NotNullable flags.

It has no relation to RequiredAttribute attribute which controls validation in forms.

DenyFiltering Flag

If set, denies filtering operations on a sensitive field. This can be useful for secret fields like PasswordHash, that shouldn't be allowed to be selected or filtered by client side.

TrimToEmpty Flag

Use this flag if you prefer to trim string fields to empty string instead of null.

When a field value is null or whitespace only, it is trimmed to empty string.

Deny Filtering

Deny filtering on this field.

Unique Flag (see UniqueAttribute)

When a field has this flag, its value is checked against existing values in database to be unique.

You can turn on this flag with Unique attribute and determine if this constraint should be checked on service level (before the check in database level to avoid cryptic constraint errors).