Dialysis is a treatment that does some of the things done by healthy kidneys. It is needed when your own kidneys can no longer take care of your body's needs. When is dialysis needed? You need dialysis when you develop end stage kidney failure --usually by the time you lose about 85 to 90 percent of your kidney function and have a GFR of <15.
1. A table is perceived as a 2-dimensional structure composed of rows and columns 2. each table row(tuple) represents a single entity occurrence within an entity set 3. each table column represents an attribute and each column has a distinct name 4. each intersection of a row and column represents a single data value 5. all values in a column must conform to the same data format 6. each column has a specific range of values known as the attribute domain
Table Keys. Each database table is consists of rows and columns. Some columns are special columns because they identify a particular record in a table. The special columns are called keys. The 2 most common keys are primary keys and foreign keys. In a database table, the column that uniquely identifies each record in the table is called a primary key.