Access files

Are quality records collected, indexed, accessed, filed, stored, maintained, and dispositioned in accordance with documented procedures ... 

The procedures that require the use or preparation of documents should also specify or invoke the procedures for their control. If the controls are unique to the document, they should be specified in the procedure that requires the document. You can produce one or more common procedures which deal with the controls that apply to all documents. Although ISO 9001 does not address all controls under clause 4.5, the provisions of clause 4.16 relating to the identification, access, filing, and storage of quality records are equally appropriate to documents in general and should be applied although it is not mandatory. 

File handling statements allow the manipulation of sequential and random access files. (Since there is considerable variation from one system to the next, the following information is given in general terms only.) Devices are treated... 

RECL returns record length in direct access file... 

NEXT REC returns number of next record in direct access file BLANK returns whether blanks or zeros specified... 

All setup data and results are stored in Data Resource Files rather than standard sequential or random access files. This has turned out to be a key feature contributing to a flexible and low maintenance system. These are ASCII files which can be typed to the screen, printed, or edited with a word processor. They contain information organized by variable name, value, and units. The following is an example of a data resource file ... 

SAS provides several ways to read Microsoft Excel and Access files. We cover many of these import methods here using Microsoft formatted versions of the laboratory normal data used previously in this chapter. The examples here are based on the capabilities found in Base SAS and SAS/ACCESS for PC Files in SAS 9.1. In Microsoft Excel, the lab normal data file might look like the following ... 

The normals ranges.mdb Microsoft Access file could be read in with the following similar SAS code. 

Be aware that the LIBNAME statement approach allows for both reading and writing to and from Microsoft Office files, which means the contents of the Microsoft Office files can be changed by SAS. There are many libref options not covered here that provide further access control features to Microsoft Excel and Access files. See the SAS documentation on the LIBNAME statement for PC files for more details. 

The interactive SAS Import Wizard provides an easy way to import the contents of Microsoft Excel and Access files into SAS. Here again, the Import Wizard is essentially a graphical user interface that builds the PROC IMPORT code for you. Begin in the interactive SAS windowing environment by selecting File from the toolbar and then Import Data... from the drop-down menu. A window like the following will appear, where you can select Microsoft Excel as a standard data source. 

The Import Wizard process for Microsoft Access files works like the one for Excel files and produces similar PROC IMPORT code. Keep in mind that text fields get a default length of 255 characters when PROC IMPORT is used with Microsoft Access files. PROC IMPORT adds a number of file security options, as well as the ability to scan memo fields via the SCANMEMO option to determine the width of character fields in Microsoft Access files. 

The SAS/ACCESS SQL Pass-Through Facility is another way for SAS to dynamically establish a connection to Microsoft Excel or Access files. You can connect to the Microsoft Excel file normal ranges.xls by using the following SAS code. 

OBTAIN AVAILABLE TABLE NAMES FROM ACCESS FILE proc sql ... 

Note that the SQL Pass-Through Facility to Microsoft Excel and Access files does default to 255 characters in length for character fields. 

Another approach to importing Microsoft Excel and Access files with SAS is to use the SAS Enterprise Guide interface. The following example imports the normal ranges.xls file using SAS Enterprise Guide 3.0. 

The process for importing Microsoft Access files into SAS Enterprise Guide is much like the process in the previous Excel example. 

Update and retrieval in direct access files using hash algorithm... 

Before any large number or alphanumeric key is used for addressing a record in the direct access file, it must be transformed into a number between 1 and N, N being the length of this file. The procedure employed for such transformation is called hash algorithm (ref. 5). 

One of the most commonly used hash algorithm employs twin prime numbers (two consecutive odd numbers that are both primes) and modulo function. If KEY is a large number (fragment ID or XOR-ed parts of chopped long string) and NP the length of the direct access file than the calculated address ADDR and the increment INCR can be obtained by the following equations ... 

Public Access File A public access file for a committee project is established as soon as the study director creates a project record in the National Academies current... 

Materials provided at a data-gathering meeting or received by mail or fax from an organization or lay persons who are not officials, agents, or employees of the National Academies are placed in the public access file. Video tapes, audio tapes, or other alternative media such as diskettes or slides or viewgraphs presented to the committee by an organization or by individuals who are not officials, agents, or employees of the National Academies are considered by the National Academies to be subject to public disclosure as well. 

Screen refresh Data entry response times Serial communication interfaces Network performance Data storage capacity Multiple user access File and data integrity Shared file access... 

Windows provides this process by allowing you to create directories, also known as folders, in which to organize files. Windows also regulates the way that files are named and what the properties of the file are. Each file created in Windows has to follow certain rules, and any program that accesses files through Windows must comply with these rules. Files created on a Windows system will follow these rules ... 

Control of quality records— Requires procedures for identification, collection, indexing, access, filing, storage, maintenance, and disposition of quality records. 

The file BND/YY/B, which after execution of LMTO (if NOEVC = 1) contains the eigenvalues and ti characters, is a random (direct) access file. This file organisation very often causes problems when LMTOPACK is implemented on machines other than Burroughs B7800. The problem is that the Burroughs, for which the programmes were written, allows sequential write and subsequent random read in a file with fixed record length, while most other machines do not. 

Problems may arise if the lengths of the inverted lists differ. This may be because certain wavenumbers are more typical than others or certain chemical structures appear more often, for example, -C-C- is more frequent than -C=C-. The solution to this problem is the appHcation of Hash coding algorithms the key is coded by a random number that is then stored in a random access file. 

Additional resources for the book can be found at http //booksupport.wiley.com Please enter the book title, editor name or ISBN to access files. 

This scheme overcomes many of the disadvantages of the other schemes it does not require an estimation of file size, files can grow organically, the file map can be copied into memory for speed of access, it facilitates direct access, file size (up to the entire capacity of a disk) is not limited artificially, and defragmentation is not required. Its one disadvantage is that of less than optimal performance in sequential processing of a file. Where such performance is desirable, it could only be achieved by putting a file on... 

---