Monday, September 24, 2007

Safety

Safety is the state of being safe, the situation of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or additional types or consequences of failure, damage, error, accidents, harm or any other event which could be considered non-desirable. This can take the form of being protected from the event or from exposure to something that causes health or reasonable losses. There also are two slightly different meanings of safety, a safety home may indicate its protection ability against external harm events, and the second that its internal installations are safe for its habitants.
Safety can be limited in relative to some guarantee or a standard of insurance to the quality and unharmful function of an object or organization. It is used in order to ensure that the object or association will do only what it is meant to do. Normative safety is a term used to explain products or designs that meet applicable design standards. Substantive safety stands for that the real-world safety history is favorable, whether or not standards are met. Perceived safety refers to the stage of comfort of users.

Thursday, September 13, 2007

Table

In relational databases, SQL databases, and flat file databases, a table is a set of data elements that is controlled using a model of horizontal rows and vertical columns. The columns are identified by name, and the rows are identified by the values appearing in a particular column division which has been identified as a candidate key. Table is another term for family although there is the difference in that a table is usually a multi-set of rows whereas a relation is a set and does not allow duplicates. A table has a particular number of columns but can have any number of rows. Besides the actual data rows, tables generally have related with them some meta-information, such as constraints on the table or on the values within particular columns.

The data in a table does not have to be actually stored in the database. Views are also relational tables, but their data is considered at query time. In non-relational systems, such as hierarchical databases, the isolated counterpart of a table is a structured file, representing the rows of a table in each record of the file and each column in a record.