Since you don’t pass a connection name to.
#Qt sync tutorial driver#
This code will create a database connection object using "QSQLITE" as the connection’s driver and "contacts.sqlite" as the connection’s database name. connectionName () 'qt_sql_default_connection' setDatabaseName ( "contacts.sqlite" ) > con > con. > from PyQt5.QtSql import QSqlDatabase > con = QSqlDatabase. Here’s a summary of the setter methods that you can use to set the more commonly used attributes or properties of a database connection:
#Qt sync tutorial password#
In general, you’ll need to set attributes such as the database name, the username, and the password for accessing the database. The specific set of attributes will depend on the driver you’re using. Once you’ve created a connection, you might need to set several attributes on it. Registering your connections with a meaningful connectionName will allow you to manage several connections in a database application. This list is a global registry that PyQt maintains behind the scenes to keep track of the available connections in an application. addDatabase() adds a database connection to a list of available connections. addDatabase() returns the newly added database connection back to the caller.Ī call to. If you already have a connection called connectionName, then that connection is removed and replaced with a new connection, and. connectionName defaults to faultConnection, which normally holds the string "qt_sql_default_connection". The second argument, connectionName, is an optional argument that holds a string with the name of the connection. The first argument, driver, is a required argument that holds a string containing the name of a PyQt-supported SQL driver. addDatabase ( driver, connectionName = QSqlDatabase. This static method takes an SQL driver and an optional connection name as arguments and returns a database connection: This class represents a connection and provides an interface for accessing the database. In PyQt, you can create a database connection by using the QSqlDatabase class.
#Qt sync tutorial install#
That makes it a user-friendly option for learning database application development.Īnother advantage of using SQLite is that the library comes shipped with Python and also with PyQt, so you don’t need to install anything else to start working with it. SQLite allows you to read and write directly to databases in your local disk without the need for a separate server process. In this tutorial, you’ll use SQLite 3, which is a well-tested database system with support on all platforms and minimal configuration requirements. To perform this step successfully, you need some general information about how your database is set up.įor example, you need to know what database management system your database is built on, and you might also need to have a username, a password, a hostname, and so on. Remove ads Creating a Database ConnectionĬonnecting your applications to a physical SQL database is an important step in the process of developing database applications with PyQt. You can connect Python to any of these database systems using a dedicated Python SQL library. You’ll find several different database management systems, such as SQLite, PostgreSQL, MySQL, MariaDB, and many others. Relational database systems and SQL are widely used nowadays.
SQL is a declarative and domain-specific programming language specially designed for communicating with databases. Most relational database systems use SQL (structured query language) for querying, manipulating, and maintaining the data held in the database. For example, in a database that stores data about the employees in a company, a specific row represents an individual employee. Each row represents a set of closely related data, and every row has the same general structure. On the other hand, the term field name is used to identify the name of a column.Įach column stores a specific kind of information, such as a names, dates, or numbers. This is what exactly happens.Note: The term field is commonly used to identify a single piece of data stored in a cell of a given record in a table. Whenever you connect a signal to a slot, you are trying to tell the compiler that whenever the signal was emitted, simply invoke the slot function. The point is if you do one connection, you need to be careful about the further overlaping connections. Signals and slots are the ones needing this connection. This is exactly what connect function does. Let's say we are building a house and we want to connect the cables. Before checking the syntax in an example, we'd better know what happens in particular. The conventional connect syntax that uses SIGNAL and SLOT macros works entirely at runtime, which has two drawbacks: it has some runtime overhead (resulting also in binary size overhead), and there's no compile-time correctness checking.
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