Question

The number of columns associated with a table is called __________

Answer 1

In a relational database, a column is a set of data values of a particular simple type, one value for each row of the database.[1] A column may contain text values, numbers, or even pointers to files in the Operating System.[2] Some relational database systems allow columns to contain more complex data types; whole documents, images or even video clips are some examples.[3] A column can also be called an attribute.

For example, a database that represents companies might have the following columns:

ID (integer identifier, unique to each row)Name (text)Address line 1 (text)Address line 2 (text)City (integer identifier, drawn from a separate table of cities, from which any state or country information would be drawn)Postal code (text)Industry (integer identifier, drawn from a separate table of industries)etc.

Each row would provide a data value for each column and would then be understood as a single structured data value, like a company perhaps, as shown above in this particular example. More formally, each row can be interpreted as a relvar, composed of a set of tuples, with each tuple consisting of the two items: the name of the relevant column and the value this row provides for that column.

Answer 2

In a relational database, a column is a set of data values of a particular simple type, one value for each row of the database.[1] A column may contain text values, numbers, or even pointers to files in the Operating System.[2] Some relational database systems allow columns to contain more complex data types; whole documents, images or even video clips are some examples.[3] A column can also be called an attribute.