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MEMORY VARIABLE

The memory of a computer is organized into a regular pattern of containers for information. These containers for information are called "words". Each one has a numeric address and each one is the same size as each of the others. For most applications, it is inconvenient to refer to portions of memory by their numeric addresses, so programming languages allow us to allocate portions of memory by name. When we store information in the memory of a computer we need to decide on how much we need for various purposes and on how it will be organized. Programming languages provide mechanism for "types" of information in memory. They also provide mechanisms to identify repetitive arrays of items of the same type and to aggregate possibly heterogeneous types under a common name.

Conceptually the memory in a computer is very much like building lots laid out by lot number on a map of the streets of a city before any houses have been built.

It may be convenient to refer to buildings by names that help us remember who lives there. In using computer memory, can be helpful to refer to allocated portions of computer memory by names that help us remember the uses to which we are putting those portions of storage. In computing we call such names "variable" names.

A house has rooms into which we may cram only a certain amount of furniture. The words in a computer have a certain capacity, given in "bits", "nibbles", "characters", "bytes", "octets" "half-words" and other terms intended to convey a sense of smaller or larger portions of a word.

On modern computers, all the units of storage are effectively given in terms of "bits". A bit is a portion of memory which can hold either a "0" or a "1". The other terms mentioned above gone through historic changes and are likely to change again. Different computer manufacturers favored different numbers of bits in, say, a byte.At present, for the most popular desk-top computers and workstations, there is considerable agreement on the following sizes:

DATA FIELD

A data field is a place where you can store data. Commonly used to refer to a column in a database or a field in a data entry form or web form.

The field may contain data to be entered as well as data to be displayed.

A specific area of an electronic record allocated for a particular category of data, usually one data element, such as a name.

A data field is the smallest subdivision of the stored data that can be accessed. A data field can be used to store numerical information such as price, count or a date or time, or even a data and time. A pair of data fields can be used in combination to hold a geo-spatial coordinate. Also, a data field can be used to hold a block of text. A data field takes up permanent storage within the data-store.

The data-store is composed of a number of data records which are, in turn, composed of a number of predefined data fields. Each of these data fields must be defined within the Load Definition File with a unique name.

Data Types
A data field can be any one of four types:

Type	Description
Signed numeric data	Includes numeric values, bit masks, times and dates. May be filtered, sorted, displayed and used within formulas of all types.
String data	Consists of text blocks not exceeding 255 characters. May be sorted and displayed by Flexible Search.
Text data	Consists of text blocks of unlimited size. May only be displayed by Flexible Search, not sorted.
Attribute data	An array of boolean flags that can be turned on or off to set and check specific criteria. An attribute type can hold up to 1024 different attribute flags, each of which can be set to either true or false. However, space should only be set aside for the number of attributes required.

Temporary Fields
In addition, a numeric, string or text data field can be marked as temporary. Temporary fields are used for calculating values or indexing data. A temporary field is like a data field, but it does not take up any permanent storage within the data-store. It is used as a scratch location for holding temprorary data while it is being indexed or used within an expression to generate permanent data for a data field.