Debian-Based Systems

Red Hat-Based Systems

Debian-Based Systems

Red Hat-Based Systems

Introduction

Both Column(TIMESTAMP(timezone=True)) and Column(DateTime) can be used to define a column in SQLAlchemy to store a date and time value. However, there are some differences between the two types of columns:

Column(DateTime)

Column(DateTime) stores a date and time value without a timezone. This means that the value will be stored in the database exactly as it is provided, without any adjustment for the timezone.

Column(TIMESTAMP(timezone=True))

Column(TIMESTAMP(timezone=True)) stores a date and time value with timezone information. This means that the value will be stored in the database with an offset from UTC that is determined by the timezone information provided with the value. When retrieving the value from the database:

Step 1: Create a Next.js Project

First, let's start by creating a new Next.js project. You can do this by running the following command in your terminal:

npx create-next-app my-app

This will create a new Next.js project with the name "my-app" in a new folder with that name.

Step 2: Install Axios

Next, we will install the axios library, which is a popular library for making HTTP requests. You can install it by running the following command in your terminal:

npm install axios

Step 3: Create the Card Component

Now, let's create a new component in our Next.js project. In this example, we will call it "Card". This component will be responsible for displaying the data that we fetch from the API. Here's the code for the "Card" component:

import React from 'react'

export default function Card({ data }) {
  return (
    <div>
      <h1>Data List</h1>
      <ul>
        {data.map(item => (
          <li key={item.id}>{item.name}</li>
        ))}
      </ul>
    </div>
  )
}

Step 4: Fetch Data with getServerSideProps

Now, we need a way to fetch the data from the API and pass it to the "Card" component. Next.js provides a built-in function called getServerSideProps that allows us to fetch data on the server side before rendering the component. Here's the code for the getServerSideProps function:

import axios from 'axios'

const API_URL = 'https://your-api-url.com/data'

export async function getServerSideProps() {
  const res = await axios.get(API_URL)
  const data = await res.data

  return {
    props: {
      data,
    },
  }
}

Introduction

Both server_default=func.now() and server_default=text('now()') can be used to specify a server-side default value for a column in SQLAlchemy, but they differ in how the default value is generated and which database backends they support.

server_default=func.now()

The func.now() approach uses SQLAlchemy's database function abstraction to generate the current timestamp. This method is database-dialect aware and automatically generates the correct SQL expression for your specific database backend.

from sqlalchemy import Column, DateTime, func

class MyModel(Base):
    __tablename__ = 'my_table'
    
    id = Column(Integer, primary_key=True)
    created_at = Column(DateTime, server_default=func.now())
    updated_at = Column(DateTime, onupdate=func.now())

Database-Specific Behavior

server_default=text('now()')

The text('now()') approach uses a plain SQL string expression. This gives you direct control over the SQL that's generated, but requires you to write database-compatible SQL yourself.

from sqlalchemy import Column, DateTime, text

class MyModel(Base):
    __tablename__ = 'my_table'
    
    id = Column(Integer, primary_key=True)
    created_at = Column(DateTime, server_default=text('now()'))
    updated_at = Column(DateTime, onupdate=text('now()'))

When to Use Which

Quick Comparison