Analogy

In terms of the mdb files, the tables or queries of the files are synonymous to the folders, particularly the folder of application documents. The record of the database table or query is likened to the application document or the biodata/resume of each applicant. The fields of the table or query are the individual pieces of information kept in the record. Hence, the name is a field, the address is another field, the educational attainment information and work history are yet another two fields of the table or query.

Tables or queries are not different for purposes of the flashcards. The difference lies in the source of information contained by them. Tables contain raw information directly entered by the user or provider. The tables would require more memory as the number of records grows. On the other hand, queries use only information contained already by these tables.

Queries

While there are several kinds of queries, only the select query is relevant to the flashcards. It is called a select query because it merely selects some fields from other tables or existing queries, and adopts them unaltered or use them either altered or computed using data from a combination of fields or other sources, and including only a limited set of records from the totality of records that the original tables hold. There are two kinds of selection, then: vertical or field selection; and horizontal or record selection.The select query, or query, in short, is a two-dimensional subset of the table or tables, presented unaltered or enhanced. It requires no additional memory to hold its derived information, other than the query definition itself.

Horizontal selection of queries can be done statically or dynamically, or both. If the limiting parameters are included in the query definition itself, this commonly called a filter. This is static horizontal selection. If the parameters are obtained before the query is performed or results displayed, this is dynamic horizontal selection. The latter is what is known as parameterized select query, or parameterized query. With this facility, there is no need to rewrite the query to vary what records may be included in the query.