python configuration virtual environment, multi version management

When developing Python applications, the system has only one version of Python 3 installed: 3.x. All third-party packages will be installed by pip in the site packages directory of Python 3. If we want to develop multiple applications at the same time, these applications will share the same python, w ...

Posted by dross613 on Sat, 27 Jun 2020 01:13:39 -0700

Day 59: Web Development Django model

by Aurora Today, I'd like to introduce the model part of Django framework. The model is a simple and clear description of real data. It contains the necessary fields and behaviors for stored data. Django follows the DRY Principle. Its goal is that you only need to define the data model, and then you don't need to care about other miscellaneous ...

Posted by gb75 on Sun, 31 May 2020 23:09:39 -0700

python sqlite tool class dynamic parameters

I've been working on sqlite and python recently After referring to the tutorials on the Internet Combined with the previous java jdbc database tool classes, write the following python connection sqlite tool classes The main reason for this is to keep a java like Object args dynamic parameter writing method is compati ...

Posted by JonathanS on Tue, 05 May 2020 17:23:14 -0700

SQLite realizes user login function

SQLite realizes user login function void login::on_LoginToMain_clicked() { //The login button needs to determine whether the user name and password correspond correctly //If there is an error, a prompt dialog box will pop up //-------------------------------------- //Use SQlite to compare user name and password QSqlDa ...

Posted by ninevolt1 on Sun, 03 May 2020 21:36:07 -0700

SQL ite3 database C language simple operation basic data search (3)

SQL ite3 database C language simple operation basic data search (3) Overview: the creation, addition, deletion, and modification of sqlite3 database have all been mentioned. Today, it is the search of the database and the application of the core of database comparison. If the previous API is used for execution, because there is a return value ...

Posted by csj16 on Thu, 30 Apr 2020 00:17:15 -0700

[open source]. NETCORE. Netframework xamarin uses ORM FreeSql to access Sqlite

1. Create project We use the console type project to test the insertion, deletion, update, query and other functions, create a console project, and use the command: dotnet new console dotnet add package FreeSql.Provider.Sqlite dotnet add package FreeSql.Repository 2. Create a solid model using System; using FreeSql.DataAnnotations; pub ...

Posted by ubaldc36 on Sat, 18 Apr 2020 09:02:50 -0700

SQLite autoincrement

SQLite's AUTOINCREMENT is a key used to automatically increment field values in a table. We can use the autoconcent keyword on a specific list name to automatically increase the value of this field when creating a table. The keyword autoconcent can only be used for integer fields. grammar CREATE TABLE table_name( column1 INTEGER AUTOINCR ...

Posted by Hendricus on Sun, 12 Apr 2020 10:04:14 -0700

dotsql of Go Language Library Series

Guide: is it very interesting to be able to carry out a single line or lines of SQL files? Today, let's introduce this interesting Library -- dotsql. Background introduction dotsql is not an ORM or a builder of SQL query statements, but a tool that can carry out several lines in an SQL file, very similar to the reading of ini configuration fi ...

Posted by ~n[EO]n~ on Thu, 02 Apr 2020 19:14:54 -0700

Introduction to libdbclient interface

This is a magical development interface! It supports access to mysql, sqlite, Dream and oracle databases! It provides a unified C++ abstract interface externally, hides the internal implementation details, and has a learning cost of 0 for users! It provides abstract result table objects (result_ta ...

Posted by khovorka on Tue, 03 Mar 2020 19:51:13 -0800

Quickly read very large tables as data frames

I have a very large table (30 million rows), and I want to load it as a data frame in R. read.table() has many convenient functions, but it seems that there are many logic in the implementation that will slow things down. As far as I'm concerned, I'm assuming that I know the type of column in advance, that the table doesn't contain any column ...

Posted by Johnlbuk on Fri, 17 Jan 2020 07:09:11 -0800