Setting up the Database and Tables
When building any software application, one needs to have a backend database to store and manage the data that the application uses. Setting up a database can seem complex, but it doesnt have to be.
In this section, we will look at creating tables and inserting data into the database.
Creating Tables
The first step in setting up a database is to create tables for the data. Tables group similar data together, and each element within a table has a specific name and data type.
A popular SQL database management system is MySQL. PostgreSQL and SQLite are two other notable database management systems.
These database management systems have their own syntax for creating tables, but the basic structure is the same. Each table has columns that define the data elements in the table.
For example, if you were building a system for a hospital, you might have a table for doctors and another for the hospital itself. The hospital table might have columns for name, address, phone number, and size of the hospital.
The doctor table might have columns for name, address, phone number, specialty, and salary.
Inserting Data
Once you have created your tables and have defined their respective columns, you need to insert data into the database. This process is accomplished using SQL data models.
SQL stands for Structured Query Language, and it is a language used to manage data stored in relational databases. To insert data into a table in a database, you would use an INSERT statement.
The statement would include the name of the table and the data you want to insert. For example, to insert data into the hospital table, the statement would look something like this:
INSERT INTO hospital (name, address, phone number, size) VALUES (‘St. Mary’s Hospital’, ‘123 Main Street’, ‘555-555-5555’, ‘500’)
Exercise Questions
Implementing an idea into a functional application involves a series of steps, one of which is creating a database. Once the database is set up, the next step is to write queries to extract information from the database.
In this section, we will look at some questions that help us understand how to fetch data from the database. Question 1: Check Database Server Version
The first question is how to check the database server version.
To do this, we use a SQL query that returns the version of the database server. Using a cursor object, we execute the query (SELECT @@version).
Then we fetch the result using cursor.fetchone. The result will be the database version.
Question 2: Fetch Hospital and Doctor Information using Hospital Id and Doctor Id
The second question is how to fetch hospital and doctor information using the hospital ID and doctor ID. The hospital table and doctor table are related, so we can join both tables to get the required information.
We use an SQL query with a JOIN operation where the hospital ID matches the specified hospital ID and doctor ID matches the specified doctor ID. The query will return the information about the doctor and the hospital where they work.
Question 3: Get the List of Doctors as per their Specialty and Salary
The third question is how to get a list of doctors as per their specialty and salary. We use a parameterized SELECT query to filter the doctors using the specialty and salary parameters.
Executing the query using a cursor object and using the fetchall method returns the list of doctors who meet the criteria. Question 4: Get a List of Doctors from a Given Hospital
The fourth question is how to get a list of doctors from a given hospital.
We use the parameterized SELECT query to get the list of doctors using a specific hospital ID. Executing the query using a cursor object and using the fetchall method returns the list of doctors working in the specified hospital.
Question 5: Update Doctor Experience in Years
The fifth question is how to update the doctor’s experience in years. We use the JOIN operation between the doctor table and the hospital table.
The JOIN operation matches the primary keys (doctor ID) of both tables. We can compute the difference between the current date and the joining date to get the number of years of experience.
We then use an UPDATE statement to update the experience in years column with the computed value.
Conclusion
Databases are integral to software development, and many modern applications rely heavily on database management systems. Understanding how to create tables and insert data into a database is critical for building functional applications.
Fetching data from the database is another important aspect of database management. Ensuring that the data is properly organized and is appropriately queried is crucial to building an effective database management system.
These exercise questions give us a glimpse of how we can extract information from the database and present that information to the users. Properly organized data management systems are fundamental to a user-friendly application, making it easy for the end-users to retrieve whatever information they need.
In conclusion, setting up a database is crucial for building functional software applications, and creating tables and inserting data are essential components of this process. Fetching data from the database is also critical to build an effective database management system.
By understanding how to extract information from the database through exercise questions such as checking the database version, fetching hospital and doctor information, getting a list of doctors based on specialty and salary, getting a list of doctors from a particular hospital, and updating doctor experience in years, we can better optimize our database management systems to improve user experiences. Properly organizing and managing data are essential for building user-friendly applications that make it easy for end-users to retrieve information, and efficient database management systems are fundamental to achieving this.