4/12/2023 0 Comments Link tables in idatabaseWhat does this mean? No two patients can have the same identifier. This indicates that the column id that has just been created in the first step can only take unique values. Integer, serial (sequential integer), varchar (a string of word/s). ![]() The columns are given a name first, and then a data type that they store. ![]() This creates the table with all the columns that we want the table to have and the type of information stored. There are three main sections in this query: In SQL language, we use the following syntax to create a table: create table patient ( name varchar, lastname varchar, hospital int, id serial, primary_doctor int ) create unique index patient_id_uindex on patient (id) alter table patient add constraint patient_pk primary key (id) Let’s break down the code into small logic steps: Tables stored in relational database and their Step 1: Create tables Before starting with the code and syntax to create tables, let’s take a look at the end result. Indirectly, patients are related to hospitals through the doctors that they are assigned. Therefore, we can say that the patient table is linked to the doctor table and the doctor table is linked to the hospital table. Obviously, a doctor could work for multiple hospitals or even multiple departments, but for the use-case, we will assume there is only one value possible. Similarly, each doctor works in a specific department within a hospital. At least that is the best case scenario that we will broach today. When a disease or condition is found the patient is given a medicine and sent home. What is a table: Database objects that hold the data in the relational databases User storyĪ person walks into the hospital and is immediately associated with a doctor. ![]() What is SQL: SQL is a domain-specific language used in programming and designed for managing data held in a relational database management system What is a RDBs: A relational database ( RDB) is a collective set of multiple data sets organised by tables, records and columns.
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