Flashcards · 0417 · Topic 18

Databases flashcards

12 cards on Topic 18, subtopics 18.1 to 18.3. Pick a subtopic or study them all.

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Name the field data types used in 0417 databases: Text (alphanumeric), numeric (integer or real), currency, date/time and Boolean (logical, yes/no).
Primary key vs foreign key: A primary key has a unique value in every record, so each record can be identified. A foreign key is a field in one table that matches the primary key of another, linking the tables.
What is a relational database, and why use one?: A database with more than one linked table. It avoids repeating the same details in many records, which saves space and reduces errors.
What is a lookup check?: A validation check that the value entered comes from a given list, such as a drop-down menu.
What must you check when importing a CSV file into a database?: The correct delimiter, whether the first row holds field names, and that each field has the right data type (e.g. a date not imported as text).

"More than 10" vs "at least 10" as search criteria: More than 10 is > 10 and excludes 10. At least 10 is >= 10 and includes 10.
What is a wildcard in a database search?: A symbol that matches part of a text value. In many systems * stands for any number of characters, so S* finds every entry starting with S.
What is a calculated field, and where is it created?: A new value worked out from other fields, e.g. Price * InStock. It is created in a query and calculated when the query runs, not stored in the table.
Which criteria find fiction books that are in stock?: Genre = "Fiction" AND InStock > 0. AND is used because both conditions, on different fields, must be true.

What is a database report?: A formatted printout of data, usually based on a query, with a title, only the fields required, readable headings and, if needed, grouping and totals.
Give three common mistakes in a database report: Truncated field headings or data, extra fields not asked for, fields in the wrong order, or a missing title or total.
Name three summary calculations a report can show: Any three of: sum (total), count, average, minimum, maximum.