Data types

A strict separation of these three types of databases is difficult hence most databases contain a mixture of data types. Therefore the classification given here is based on the predominating data type. For example, the major emphasis of a patent database is on hterature, whereas it also comprises numeric and structural data. Another type is the integrated database, which provides a supplement of additional information, especially bibhographic data. Thus, different database types are merged, a textual database and one or more factual databases. 

Ohject-bastd model data representation in many differenl data types supports temporal and higher- dimensional data objecis can be reused difficull to design DHMS slow perfonnanee... 

Compounds are stored in reaction databases as connection tables (CT) in the same manner as in structure databases (see Section 5.11). Additionally, each compound is assigned information on the reaction center and the role of each compound in the specific reaction scheme (educt, product, etc.) (see Chapter 3). In addition to reaction data, the reaction database also includes bibliographic and factual information (solvent, yield, etc.). All these different data types render the integrated databases quite complex. The retrieval software must be able to recall all these different types of information. 

Structure descriptors can be distinguished by the data type Table 8-1) of the descriptor and the molecular representation of the compound (Table 8-2). 

Table 8-1. Classification of molecular descriptors by descriptor s data type.

Data type Example of a descriptor with this type of data... 

Molecules can be represented by structure descriptors in a hierarchical manner with respect to a) the descriptor data type, and b) the molecular representation of the compound. 

Chemical data are usually multidimensional in nature where one data object is defined through several data components. This data type is called multivariate. 

Large data sets such as screening data or results obtained by combinatorial experiments are made up of a large number of data records. Hence a data record may represent a chemical reaction or substance, for example its corresponding variables will define the corresponding reaction conditions or biological activities. Depending on the dimensionality or data type of the information, one-, two-, multidimensional, or specific data types can be identified. 

Many databases can be classified in multiple ways because of multiple type data, eg, text and numeric data, text and image data, image and audio data, etc. Also included in the data presented in Table 1 are two additional classes of databases, electronic services and software. Both of these data types could also be classed by form of representation because of use of words and numbers. However, the way in which these databases are used is different and they have special characteristics. Thus they are presented as additional classes. Whereas electronic information services such as bulletin boards, electronic mail, and electronic conferencing contain data that are transitory and nonarchival, these must be included among databases because several of the principal vendors seU these services in the same way as database search services are sold. 

If Modify is chosen from the menu, a drop-down menu with the available data types appears Family, Event " ees, Systems, End States, Basic Events, Attributes, Analysis Types, Gates, Hi rams, P Ls, Change Sets, and Flag Sets. After selecting an option, a dialog containing a li f of all records for the selected data type appears. The functions Add, Copy, Modify, and C be selected from another pop-up menu. 

Logical—Data type w ith only two possible values True (represented as 1) and False (represented as 0), also referred to as Boolean. 

Data Types. See the scuion Statements" foi forms of declaration of type. 

Type declaration—Specifies data type to be represented by a variable name (overrides defaults), e.g.,... 

Specifications for time four most common data types... 

Data Types (Data structures of ail types, predefined and user-defined, must be declared see Statements for type declaration form.)... 

Type declaration—Must be placed after CONST sequence and before variable declarations used to define nev (not predefined) data types either as a range of values or as specific values within parentheses and to define arrays, records, and files. User-defined scalar types are ordered in increasing lefl to right sequence. For example. 

There are two major data-type classifications time-domain and frequency-domain. Each of these can be further divided into steady state and dynamic data formats. In turn, each of these two formats can be further divided into single-channel and multi-channel. 

Vibration profiles can be acquired and displayed in one of two data types (1) time-domain or (2) frequency-domain. 

The data logger or microprocessor selected by your predictive maintenance program is critical to the success of the program. There is a wide variety of systems on the market that range from handheld overall value meters to advanced analyzers that can provide an almost unlimited amount of data. The key selection parameters for a data acquisition instrument should include the expertise required to operate, accuracy of data, type of data, and manpower required to meet the program demands. 

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