The current paper discusses the concept of relational tables and dwells on the conceptual development of a database. The database deals with data on infectious diseases. The author of the paper specifies the unique names of the relational tables, attributes, and data characteristics. All the primary keys are identified and discussed. The author uses scholarly literature to approve the design choices made concerning the data input and data view. The concept of relational tables Relational databases are based on the concept of relational tables. This means that each of the tables consists of the fields (also called attributes) and lines of data that are termed records. There are several commandments that a relational database should comply with. First, there cannot be two identical records in a table. This postulate is based on a mathematical axiom presupposing relations within the table. Second, the attributes are added to the table in a certain order that is defined when creating a table. A table may not have a single record, but it is required to have at least one field (attribute). Third, each attribute should have a unique name, and all the values should be of the same data type (E.g., numeric, text, date, etc.). The most important commandment is that there may be only one atomary value (not a group of values) on the junctions of each of the fields and records. The tables that satisfy the latter commandment are called normalized. One of the important notions connected to the concept of relational tables is the term “primary key.” The values of this attribute are required to be different in all the lines of the database (records). The selection of a primary key (PK) is a rather important task, and one should proceed with caution before choosing it. Another term that is connected to the PK is the foreign key (FK). It is usually utilized to show relations between the tables as each of the FK values correlates to a PK from another table. Relational tables The concept of the database includes five tables. The following representation comprises the table names and data types for each field. Nurse         Data type Nurse_ID      int       Last_Name     text      First_Name    text      Patient_ID    int       Screening_ID  int        Figure 1. Table “Nurse.” Patient             Data type Patient_ID          int       SSN_Number          int       Patient_Last_Name   text      Patient_First_Name  text      Infection_ID        text      Screening_ID        int        Figure 2. Table “Patient.” Screening_Result  Data type Screening_ID      int       Screening_Status  bool      Date              timestamp  Figure 3. Table “Screening Result.” Screening         Data type Screening_ID      int       Screening_Status  bool      Patient_ID        int       Nurse_ID          int        Figure 4. Table “Screening.” Infection        Data type Infection_ID     int       Infection_Title  text       Figure 5. Table “Infection.” Primary and secondary keys The primary key for the table Nurse is the field Nurse_ID as it is an exclusive value for the reason that there cannot be two nurses with the same identification number. The foreign key for the table Nurse is the field Patient_ID as