9 Databases Flashcards
What is a database?
A collection of data about objects stored in tables. It is application software used to store and manipulate data
What is a table?
A set of data about one type of object, made up of fields, in database
What is a field?
An individual piece of data stored about an object in a database
What is a record?
A collection of fields about one object, in a database
What are the core parts of a database?
Tables, fields, records (and maybe objects)
What does each field have?
A specific data type
What are the common database data types and what are their details?
Text / alphanumeric - any combination of letters, symbols and numbers, character - single letter, number or symbol, boolean - one of two values, integer - whole number, real - number with decimal part, date / time - a data and/or time
What is a primary key and what are its details?
A unique field in a database which uniquely identifies a record. It does not appear twice in different records
What is SQL (Structured Query Language) and what can it do?
A standard language used in databases to define tables, change tables, add data to tables, search for data from tables (query) and perform calculations using data from tables
What does a SELECT… FROM statement in SQL allow you to do?
Allows you to select a set of fields from a table. All data in each field will be returned
Do field and table names in SQL have to be exact?
Yes. It is case sensitive
What is the WHERE clause in a SELECT statement in SQL?
A clause which allows you to only select specific data which meets certain conditions
What is a logical operator in SQL and what are some examples?
A symbol that performs a comparison resulting in True or False. Can be =, <, <=, >, >=, <> (not equal to)
What is a Boolean operator in SQL and what are some examples?
A symbol that joins multiple logical comparisons. Can be AND (returns data meeting both conditions), OR (returns data meeting one or both conditions), NOT (returns data that doesn’t meet the condition)
When more than one condition is used in SQL, what is required?
Boolean operator
