postgresql create database if not exists

POSTGRESQL CREATE DATABASE IF NOT EXISTS HOW TO
POSTGRESQL CREATE DATABASE IF NOT EXISTS CODE

POSTGRESQL CREATE DATABASE IF NOT EXISTS HOW TO

Each time a migration is performed, a script is created with details on how to convert the database to the new version ( upgrade) and how to reverse the migration to the old version ( downgrade).

POSTGRESQL CREATE DATABASE IF NOT EXISTS CODE

Using the Alembic library, we can auto-generate SQA code to transform the database from the old version into the new version. This is what database migrations are for. We could just go into pgAdmin and issue some SQL, but there's a better way to do it in Python and keep track of the changes. If there was any user generated data, we would lose it. If we recreated the database, we would have to go back and insert all of the data again. Let's say we wanted to add some new data to the Books model, such as a new column for the price of the book, but we can't just drop_all and create_all because now there's users relying on the database being available. Want to learn more?See Best Data Science Courses of 2023 View. Setting up Postgres is a fairly simple Windows download and install. This is handy for things like autocompleting search fields in websites, as well as data science projects using natural language processing. Postgres can easily store vector representations of text you're storing and allow super fast queries on it. inet/cidr - store IP addresses, which is useful for some web apps.date and timestamp - ability to index and sort by dates and times, also useful for time series data.MONEY - makes it easier to work with time series data, like that of stocks.JSON - store JSON arrays with ability to query against them.Some notable examples of column types that Postgres has but SQLite doesn't are: Postgres has a richer set of column data types than SQLite. For example:īecause Postgres is usually on a server in the cloud, like on Amazon or Google, any number of users or apps can connect to it at once and perform operations.įor example, imagine you're working with someone in a different country how would you both be able to interact with a SQLite file? Where would you put it? How would you both be able to make a connection to it? For a Postgres server, each of you would get use a connection string that contains an IP and Port to the Postgres instance, allowing a socket connection to the database. Postgres is a totally free, open-source database and supports many powerful features that are absent in SQLite.

Postgresql create database if not exists