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Farhana

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What is a SAS Library and how is it different from metadata?


I would like to know the difference between the SAS Library and metadata. I was told that these days, many SAS processes rely increasingly on metadata. Why is this so?



- Farhana
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Nicoleswy

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SAS library is simply a collection of SAS files that are stored in the same folder or directory on your computer. Other files can be stored in the same folder or directory, but only the files that have SAS file extensions are recognized as part of the SAS library.

Whereas the SAS Metadata Server is a centralized resource for storing, managing, and delivering metadata for SAS applications across the enterprise. The SAS Metadata Server enables centralized control so that all users access consistent and accurate data. Access to data and metadata is secured through a metadata-based authorization layer, which supplements protections from the host environment and other systems. The functionality of the SAS Metadata Server is provided through the SAS Open Metadata Architecture, which is a metadata management facility that provides common metadata services to applications.

The reasons SAS processes rely increasingly on metadata are because:

  1. Accessing the physical data is expensive, in terms of I/O processing. Metadata can tell you about available data sources without expensive queries to the database.
  2. Metadata is critical for building robust ETL processes and understanding impact of changes to downstream outputs (Example: "what reports are impacted if I change the name of this column?"). (You typically use SAS Data Integration Studio for this work.)
  3. Metadata is easier to "secure", allowing you to assign privileges for users and groups to see only what you want them to see about the available data sources. (You use SAS Management Console for this work.)
  4. Metadata can be used to "repackage" your data sources and represent them in friendlier business views (using SAS information maps, for example) without the expense of keeping multiple copies of the same data.


- Nicoleswy
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Scottt

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A SAS library is a folder located on a user's disk drive or on the internet that is specially designated for use by SAS. SAS libraries allow users to safely store things like data sets and user-defined formats so that they can be accessed without having to reload or re-read them from an external file every time SAS is started.

Whereas the SAS Metadata Server is the most critical software component in the SAS Intelligence Platform. All of the client applications and the other SAS servers that are part of the platform depend on the SAS Metadata Server and cannot operate without it. The SAS Metadata Server is a multi-user server that serves metadata from one or more SAS Metadata Repositories to all of the SAS Intelligence Platform client applications in your environment. The SAS Metadata Server enables centralized control so that all users access consistent and accurate data. The functionality of the SAS Metadata Server is provided through the SAS Open Metadata Architecture, which is a metadata management facility that provides common metadata services to applications. One metadata server supports all of the SAS applications in your environment and can support hundreds of concurrent users. This architecture enables the following: the exchange of metadata between applications, so that applications can work together more easily. centralized management of metadata resources. Because there is a common framework for creating, accessing, and updating metadata, it is easier to manage the applications that rely on this metadata. The SAS Metadata Server stores information about the following: the enterprise data sources and data structures that are accessed by SAS applications resources that are created and used by SAS applications, including information maps, OLAP cubes, report definitions, stored process definitions, and scheduled jobs the servers that run SAS processes the users and groups of users that use the system, and the levels of access that users and groups have to resources



- Scottt
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155952D

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SAS library is simply a collection of SAS files that are stored in the same folder or directory on your computer. Other files can be stored in the same folder or directory, but only the files that have SAS file extensions are recognized as part of the SAS library.

The META engine is a special SAS library engine that enforces the metadata-centric view of a SAS library. The engine provides a level of indirection between your SAS programs and the physical location of your data, allowing you to reference a library definition that exists in metadata.

SAS libraries defined in metadata have two main components:

  1. The library definition, which describes how to assign the library. This information includes the path, engine, and any library-specific options that are needed. These parts of the definition correspond to the syntax of the traditional LIBNAME statement that most SAS programmers are familiar with.
  2. The table definitions, which describe the tables and columns available within the library. Table definitions are added to metadata in three main ways:

    • Using SAS Management Console, you can select the library and use the Import Tables feature, which allows you to connect to the library, view the physical tables that exist, and import the desired table definitions into metadata.

    • Using the METALIB procedure from within a SAS session; this is a programmatic method of importing table metadata, synchronizing metadata with the physical contents of the library. You can also use the Tools->Update Library Metadata feature in SAS Enterprise Guide to generate PROC METALIB code.

    • Using SAS Data Integration Studio to build a data warehouse. The process of building a data warehouse updates metadata about libraries, tables, and columns.



- 155952D
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Lili96

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SAS Enterprise Guide provides access to libraries that are defined in a SAS metadata repository, in addition to those libraries that are defined within a SAS session using the LIBNAME statement. When accessing a SAS library via its definition in metadata, SAS Enterprise Guide usually uses the META library engine. The META engine provides a layer of indirection between the SAS session and the physical data store, and it behaves according to the rules defined within the SAS metadata repository. Because the META engine behaves differently that the "native" library engine (such as BASE for file-based data, or a SAS/ACCESS library for DBMS data), it's important for SAS administrators to understand the different behaviors and how these can be controlled.

ABOUT SAS METADATA LIBRARIES

SAS libraries defined in metadata have two main components:

  1. The library definition, which describes how to assign the library. This information includes the path, engine, and any library-specific options that are needed. These parts of the definition correspond to the syntax of the traditional LIBNAME statement that most SAS programmers are familiar with. An administrator can attach authorization details to a library definition, controlling which users can view/access the contents of the library and change its contents.

  2. The table definitions, which describe the tables and columns available within the library. Table definitions are added to metadata in three main ways:

1.Using SAS Management Console, you can select the library and use the Import Tables feature, which allows you to connect to the library, view the physical tables that exist, and import the desired table definitions into metadata.

2.Using the METALIB procedure from within a SAS session; this is a programmatic method of importing table metadata, synchronizing metadata with the physical contents of the library.

You can also use the Tools->Update Library Metadata feature in SAS Enterprise Guide to generate PROC METALIB code.

3.Using SAS Data Integration Studio to build a data warehouse. The process of building a data warehouse updates metadata about libraries, tables, and columns. Administrators can also attach authorization details to table definitions, controlling which users can access specific tables and even specific columns within those tables. Library and table metadata is a prerequisite for many data-related features in SAS clients and solutions. For example, if you want to provide a business view of data by defining information maps in SAS Information Map Studio, you must first add metadata about the tables and columns that feed into those information maps.

with reference:http://support.sas.com/documentation/onlinedoc/guide/EG43MetaLibraries.pdf



- Lili96
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AlvinYap

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SAS library is simply a collection of SAS files that are stored in the same folder or directory on your computer. Other files can be stored in the same folder or directory, but only the files that have SAS file extensions are recognized as part of the SAS library. SAS has a built-in temporary library called Work. The Work library is a place to store data you are working on in your current session. Because the Work library is temporary, you will lose any datasets you created and stored in the Work library when you close out of your SAS session.


A metadata-bound library is a physical library that is tied to a corresponding metadata object.

Each physical table within a metadata-bound library has information in its header that points to a specific metadata object (a secured table object). The pointer creates a security binding between the physical table and the metadata object. The binding ensures that SAS universally enforces metadata-layer permission requirements for the physical table—regardless of how a user requests access from SAS.

Access from SAS to data within a metadata-bound library is provided only if all of the following conditions are met:

-The requesting user can connect to the metadata server in which the corresponding object is stored.

-The requesting user’s metadata identity has all required metadata-layer effective permissions for the requested action.

-The host identity with which the data is retrieved has all required host-layer access to the data.



- AlvinYap
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SandyTang

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A SAS library, use a one-level name to create and access files that are not deleted at the end of your SAS session.



- SandyTang
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Bjergsen

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SAS library is a collection of SAS files stored in the same place , example your desktop or Z drive . Other files can be stored in the same folder or directory, but only the files that have SAS file extensions are recognized as part of the SAS library.

SAS libraries defined in metadata have two main components:

The library definition, which describes how to assign the library. This information includes the path, engine, and any library-specific options that are needed. The table definitions, which describe the tables and columns available within the library.



- Bjergsen
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