When you need to store large amounts of character data in your SQL database, the TEXT data type provides a flexible solution. Unlike CHAR or VARCHAR, which are designed for smaller or moderately-sized strings, TEXT is specifically intended for long-form content. This makes it ideal for storing things like user comments, product descriptions, blog posts, or any other field where the length of the data might be highly variable or exceed the practical limits of VARCHAR.

The TEXT type offers several advantages. It allows you to store strings of virtually unlimited length (the practical limit is determined by your database system, but it is typically very large). This means you do not need to predict or enforce a maximum size when designing your schema. However, there are some trade-offs. TEXT columns may have restrictions on indexing and certain operations compared to VARCHAR. For example, you might not be able to use them as primary keys or in unique constraints, and some databases limit the use of TEXT columns in certain expressions or sorting operations.

To illustrate how you might use a TEXT column in practice, consider a table for storing user comments on products or articles.

CREATE TABLE comments_example (
    id SERIAL PRIMARY KEY,
    user_id INTEGER NOT NULL,
    comment_text TEXT
);

In this example, the comment_text column uses the TEXT data type. This allows users to leave comments of any length, whether it's a quick note or a detailed review. You would choose TEXT over VARCHAR when you expect that the data could be very long or unpredictable in size, and you do not want to enforce a strict length limit. For instance, if you set a VARCHAR(255), any comment longer than 255 characters would be truncated or rejected, which could frustrate users. By using TEXT, you ensure that the database can accommodate comments of any reasonable length without modification.

On the other hand, for fields like usernames or short titles, where you know the maximum length in advance, VARCHAR remains a better choice because it can be more efficient for storage and indexing. But for long-form content, TEXT is the preferred type.

Let's see how you can insert a long string into a TEXT column.

INSERT INTO comments_example (user_id, comment_text)
VALUES (42, 'This is a very long comment. It can contain as much text as needed, including multiple paragraphs, special characters, or even pasted content from other sources. The TEXT type ensures that the entire comment is stored without worrying about length limits.');