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Welcome to this interesting topic where we dive deep into the world of SQL by designing a pet adoption application and matching system. This approach illustrates the power of SQL in building database applications. For this exercise, let’s assume that we have three tables: ‘Pets’, ‘Adopters’, and ‘Matches’.
Step 1: Creating the tables
Let’s first define our tables with the required columns – Pets will store details about the pets, Adopters will contain information about potential adopters, and Matches will store the mapping between pets and their potential adopters.
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CREATE TABLE Pets ( PetID INT PRIMARY KEY, Name VARCHAR(100), AnimalType VARCHAR(100), Age INT ); CREATE TABLE Adopters ( AdopterID INT PRIMARY KEY, Name VARCHAR(100), PreferredAnimalType VARCHAR(100) ); CREATE TABLE Matches ( MatchID INT PRIMARY KEY, AdopterID INT, PetID INT, FOREIGN KEY (AdopterID) REFERENCES Adopters(AdopterID), FOREIGN KEY (PetID) REFERENCES Pets(PetID) ); |
Step 2: Inserting Data
The next stage is feeding data into these tables for the pets, adopters, and potential matches. Here’s an example:
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INSERT INTO Pets VALUES (1, 'Tom', 'Cat', 2); INSERT INTO Adopters VALUES (1, 'Jerry', 'Cat'); INSERT INTO Matches VALUES (1, 1, 1); |
Step 3: Querying Data
Now, let’s see how to generate a list of potential matches for each adopter based on their preferred animal type. For this, we can join the ‘Matches’, ‘Pets’, and ‘Adopters’ tables.
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SELECT Adopters.Name AS AdopterName, Pets.Name AS PetName FROM Matches JOIN Adopters ON Matches.AdopterID = Adopters.AdopterID JOIN Pets ON Matches.PetID = Pets.PetID WHERE Adopters.PreferredAnimalType = Pets.AnimalType; |
Conclusion
SQL allows us to create powerful database applications, such as a matching system for pet adoptions. With the above examples, we’ve only scratched the surface of what’s possible. By properly structuring your data and leveraging the power of SQL, you can design seemingly complex applications with relative ease.