SQL and PyQt

Learn how we can implement and use SQL with PyQt.

PyQt's model/view classes

One of the few convenience classes PyQt offers for working with data is QTableWidget. A table of items can be created using QTableWidget, a list of things can be displayed using QListWidget, and a tree-like structure can be provided using QTreeWidget. The view, model, and delegate classes are all combined into one category in these widgets, which offer all the tools required to work with data. However, compared to dealing with the model/view structure, these classes are less versatile and are more centered on item-based interfaces. These widgets all get their functionality for controlling headers and selecting items from the abstract class QAbstractItemView.

An abstract class offers the interfaces between other parts, offering functionality and default feature implementation.

  • Models: Each model is built on the QAbstractItemModel class, which defines the interface for views and delegates to utilize when requesting data. Models can be used to manage lists, tables, or trees. Data can be stored in various ways, including databases, files, distinct classes, and Python data structures. QStandardItemModel, QFileSystemModel, and models related to SQL are a few additional model classes.

  • Views: All views, such as QListView, QTableView, and QTreeView, are based on QAbstractItemView and used to show data items from a data source.

  • Delegates: QAbstractItemDelegate is the introductory class in charge of drawing items from the model and providing an editor widget for editing things. For instance, the editor widget, such as QLineEdit, is positioned directly on top of the item while editing a cell in a table.

What is SQL?

A computer language called SQL (Structured Query Language) was explicitly created for interacting with databases. Tables are used to organize the data that is kept in databases. The columns of the tables are referred to as fields, while the rows are known as records. Only one type of data can fit in each column, such as names, dates, or numbers.

We can use SQL to query the information held in relational databases, which are collections of data items with predefined relationships between different tables identified by a unique identifier called a foreign key. In a relational database, a schema is made up of several tables, a database is made up of several schemas, and the databases are kept on a server. Multiple users can access and manipulate the data simultaneously with relational databases. Due to this, connecting to a database frequently necessitates a user logging in with a username and password.

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