Database Schema

Get a look behind the scene! This page describes the database schema. Signumsoft .NET Object Database stores data in a generic way. Table structure never needs to be changed. Object relational mapping (ORM, O/R, OR-Mapper) is NOT necessary! Data is stored in the following tables:

Database Schema

Table DefinitionName

The table "DefinitionName" serves as simple dictionary. Every existing class name and every existing field name of the objects found by .NET Reflection in the program code is stored here. To every name is a unique identifier assigned.

Field Name	Type	Nullable	Reference	Description
Id	Guid	No	No	Unique identifier serves as dictionary key.
Name	String	No	No	Dictionary Value. Can be a class name or a field name.

Index Name	Columns	Unique		Description
IX_DefinitionName	Name	Yes		Makes sure that same name does not appear twice in database dictionary.

Table StorageObject

Table "StorageObject" stores all object instances. Every time an object is created a record is added to this table.

Field Name	Type	Nullable	Reference	Description
Id	Guid	No	No	Unique identifier for object. Every object needs to be uniquely identified.
ClassNameId	Guid	No	Yes	Reference to class name in table "DefinitionName".

Table StorageField

Table "StorageField" stores all object values. Every time an object value is set, a record is added to this table.

Field Name	Type	Nullable	Reference	Description
Id	Guid	No	No	Unique identifier for field. Every field is uniquely identified.
ObjectId	Guid	No	Yes	Reference to object to which this field belongs.
FieldNameId	Guid	No	Yes	Reference to field name in table "DefinitionName".
Key_	SqlVariant	No	No	For lists the index. For Dictionaries the key. For one to one references: Always 0.
Value	SqlVariant	Yes	No (Yes)	Field Value. Can be reference to an object.

Index Name	Columns	Unique		Description
IX_DefinitionStorageField	ObjectId, FieldNameId, Key_	Yes		Make sure that same key on same field on same object does not exist twice.

CacheClassTree

Table "CacheClassTree" contains the hierarchical inheritance structure of the classes. It's called cache since the master of this information is the program code. Inheritance information is just mirrored on the database. This information is used in the generated SQL views.

Field Name	Type	Nullable	Reference	Description
Id	Guid	No	No	Primary Key
ClassNameId	Guid	No	Yes	Reference to class name in table "DefinitionName".
ClassNameIdEquals	Guid	No	Yes	Reference to a (base) 'class name' in table "DefinitionName".