![]() With priming, a brief imperceptible stimulus temporarily provides enough activation to a schema so that it is used for subsequent ambiguous information. Although this may suggest the possibility of subliminal messages, the effect of priming is so fleeting that it is difficult to detect outside laboratory conditions. Furthermore, the. “schemata can represent knowledge at all levels. Failure to activate adequate schema when reading a text has shown to result in bad comprehension 15). In psychology and cognitive science, a schema (plural schemata or schemas) describes a pattern of thought or behavior that organizes categories of information and the relationships among them. Relational databases contain a catalog that describes the various elements in the system. The catalog divides the database into sub-databases known as schema. A database schema enables you to logically group together objects such as tables, views, and stored procedures. Without a defined schema, you cannot write to the catalog. SAP HANA Extended Application Services ( SAP HANA XS) enables you to create a database schema as a transportable design-time file in the repository. Repository files can be read by applications that you develop. If your application refers to the repository (design-time) version of a schema rather than the runtime version in the catalog, for example, by using the explicit path to the repository file (with suffix), any changes to the repository version of the file are visible as soon as they are committed to the repository. There is no need to wait for the repository to activate a runtime version of the schema. If you want to define a transportable schema using the design-time hdbschema specifications, use the configuration schema illustrated in the following example: string schema_name The following example shows the contents of a valid transportable schema-definition file for a schema called MYSCHEMA: schema_name=”MYSCHEMA”; The schema is stored in the repository with the schema name MYSCHEMA as the file name and the suffix.hdbschema, for example, MYSCHEMA.hdbschema. Note A schema generated from an.hdbschema artifact can also be used in the context of Core Data Services (CDS). Schema Activation If you want to create a schema definition as a design-time object, you must create the schema as a flat file. You save the file containing the schema definition with the suffix.hdbschema in the appropriate package for your application in the SAP HANA repository. You can activate the design-time objects at any point in time. Note On activation of a repository file, the file suffix, for example,.hdbschema, is used to determine which runtime plugin to call during the activation process. The plug-in reads the repository file selected for activation, parses the object descriptions in the file, and creates the appropriate runtime objects. ![]() If you activate a schema-definition object in SAP HANA, the activation process checks if a schema with the same name already exists in the SAP HANA repository. If a schema with the specified name does not exist, the repository creates a schema with the specified name and makes _SYS_REPO the owner of the new schema. Note The schema cannot be dropped even if the deletion of a schema object is activated. If you define a schema in SAP HANA XS, note the following important points regarding the schema name: • Name mapping The schema name must be identical to the name of the corresponding repository object. • Naming conventions The schema name must adhere to the SAP HANA rules for database identifiers. In addition, a schema name must not start with the letters SAP*; the SAP* namespace is reserved for schemas used by SAP products and applications. • Name usage The Data Definition Language (DDL) rendered by the repository contains the schema name as a delimited identifier. In this section • • • The schema is the Active Directory component that defines all the objects and attributes that the directory service uses to store data. Active Directory stores and retrieves information from a wide variety of applications and services. So that it can store and replicate data from a potentially infinite variety of sources, Active Directory standardizes how data is stored in the directory. By standardizing how data is stored, the directory service can retrieve, update, and replicate data while ensuring that the integrity of the data is maintained. The directory service uses objects as units of storage. All objects are defined in the schema. Each time that the directory handles data, the directory queries the schema for an appropriate object definition. Based on the object definition in the schema, the directory creates the object and stores the data. Object definitions control the types of data that the objects can store, as well as the syntax of the data. Using this information, the schema ensures that all objects conform to their standard definitions. As a result, Active Directory can store, retrieve, and validate the data that it manages, regardless of the application that is the original source of the data. Only data that has an existing object definition in the schema can be stored in the directory. ![]() ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
March 2018
Categories |