--- title: Attributes ms.custom: "" ms.date: "03/15/2017" ms.prod: sql ms.prod_service: "mds" ms.reviewer: "" ms.technology: master-data-services ms.topic: conceptual helpviewer_keywords: - "free-form attributes [Master Data Services]" - "attributes [Master Data Services], about attributes" - "attributes [Master Data Services], file attributes" - "file attributes [Master Data Services]" - "attributes [Master Data Services], free-form attributes" - "attributes [Master Data Services]" ms.assetid: 95ecb75f-c559-41c3-933c-40ae60a4c2fd author: lrtoyou1223 ms.author: lle --- # Attributes (Master Data Services) [!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md-winonly](../includes/appliesto-ss-xxxx-xxxx-xxx-md-winonly.md)] Attributes are objects that are contained in [!INCLUDE[ssMDSshort](../includes/ssmdsshort-md.md)] entities. Attribute values describe the members of the entity. An attribute can be used to describe a leaf member, a consolidated member, or a collection. ## How Attributes Relate to Other Model Objects You can think of an attribute as a column in an entity table. An attribute value is the value used to describe a specific member. ![Master Data Services Entity Represented as Table](../master-data-services/media/mds-conc-entity-table.gif "Master Data Services Entity Represented as Table") When you create an entity that contains many attributes, you can organize the attributes into attribute groups. For more information, see [Attribute Groups (Master Data Services)](../master-data-services/attribute-groups-master-data-services.md). ## Required Attributes When you create an entity, the Name and Code attributes are automatically created. Code requires a value and must be unique within the entity. You cannot remove the Name and Code attributes. ## Attribute Types There are three types of attributes: - Free-form attributes, which allow free-form input for text, numbers, dates, or links. - Domain-based attributes, which are populated by entities. For more information, see [Domain-Based Attributes (Master Data Services)](../master-data-services/domain-based-attributes-master-data-services.md). - File attributes, which are used to store files, documents, or images. File attributes are intended to help with the consistency of your data by requiring files to have a specific extension. File attributes cannot be guaranteed to prevent a malicious user from uploading a file of a different type. ### Numeric Free-Form Attributes Numeric free-form attributes require special handling, because numeric free-form attribute values are limited to the **SqlDouble** value type. By default, a **SqlDouble** value contains 15 decimal digits of precision, although a maximum of 17 digits is maintained internally. The precision of a floating-point number has several consequences: - Two floating-point numbers that appear equal for a particular precision might not compare equal because their least significant digits are different. - A mathematical or comparison operation that uses a floating-point number might not yield the same result if a decimal number is used because the floating-point number might not exactly approximate the decimal number. - A value might not *roundtrip* if a floating-point number is involved. A value is said to roundtrip if an operation converts an original floating-point number to another form, an inverse operation transforms the converted form back to a floating-point number, and the final floating-point number is equal to the original floating-point number. The roundtrip might fail because one or more least significant digits are lost or changed in a conversion. ## Attribute Examples In the following example, the entity has the attributes: Name, Code, Subcategory, StandardCost, ListPrice, and FilePhoto. These attributes describe the members. Each member is represented by a single row of attribute values. ![Bike Product Entity Table](../master-data-services/media/mds-conc-entity-table-w-data.gif "Bike Product Entity Table") In the following example, the Product entity contains: - The free-form attributes of Name, Code, StandardCost and ListPrice. - The domain-based attribute of Subcategory. - The file attribute of FilePhoto. Subcategory is an entity that is used as a domain-based attribute of Product. Category is an entity that is used as a domain-based attribute of Subcategory. Like the Product entity, the Category and Subcategory entities each contain the default Name and Code attributes. ![Product Entity Tree Structure](../master-data-services/media/mds-conc-entity-ui.gif "Product Entity Tree Structure") ## Related Tasks |Task Description|Topic| |----------------------|-----------| |Create a new free-form text attribute.|[Create a Text Attribute (Master Data Services)](../master-data-services/create-a-text-attribute-master-data-services.md)| |Create a new free-form numeric attribute.|[Create a Numeric Attribute (Master Data Services)](../master-data-services/create-a-numeric-attribute-master-data-services.md)| |Create a new free-form link attribute.|[Create a Link Attribute (Master Data Services)](../master-data-services/create-a-link-attribute-master-data-services.md)| |Create a new file attribute.|[Create a File Attribute (Master Data Services)](../master-data-services/create-a-file-attribute-master-data-services.md)| |Create a new domain-based attribute.|[Create a Domain-Based Attribute (Master Data Services)](../master-data-services/create-a-domain-based-attribute-master-data-services.md)| |Change the name of an existing attribute.|[Change an Attribute Name and Data Type (Master Data Services)](../master-data-services/change-an-attribute-name-and-data-type-master-data-services.md)| |Add existing attributes to a change tracking group.|[Add Attributes to a Change Tracking Group (Master Data Services)](../master-data-services/add-attributes-to-a-change-tracking-group-master-data-services.md)| |Delete an existing attribute.|[Delete an Attribute (Master Data Services)](../master-data-services/delete-an-attribute-master-data-services.md)| |Change the order of attributes.|[Change the Order of Attributes](../master-data-services/change-the-order-of-attributes.md)| |Create a date attribute|[Create a Date Attribute (Master Data Services)](../master-data-services/create-a-date-attribute-master-data-services.md)| ## Related Content - [Domain-Based Attributes (Master Data Services)](../master-data-services/domain-based-attributes-master-data-services.md) - [Attribute Groups (Master Data Services)](../master-data-services/attribute-groups-master-data-services.md) - [Members (Master Data Services)](../master-data-services/members-master-data-services.md) - [Leaf Permissions (Master Data Services)](../master-data-services/leaf-permissions-master-data-services.md)