For testing purposes, I clear (delete) each table before executing the code.
for table in reversed (db.metadata.sorted_tables):
engine.execute(table.delete())
do_stuff() However, the id valu
Category: Database
The database is a warehouse that organizes, stores and manages data according to the data structure. It was created more than 60 years ago. With the development of information technology and the market, especially after the 1990s, data management is no longer just It is to store and manage data, and transform it into various data management methods required by users. There are many types of databases, from the simplest tables that store various data to large-scale database systems that can store massive amounts of data. They have been widely used in all aspects.
NOSQL – Cassandra column key automatically increment
I am trying to understand Cassandra and how to build my column family (CF), but since I am used to relational databases, it is difficult.
For example , If I create a simple user CF and I try
Running errors in PostgreSQL
CREATE OR REPLACE FUNCTION msgfailerror() RETURNS trigger AS
‘ BEGIN
IF NEW.noces< new.first_column THEN
RAISE EXCEPTION ' cannot have a negative salary';
END IF;
return new;
END' LANGUAG
PostgreSQL – PLPGSQL function returns another function value
I have a function func1() that returns integers.
I want to write another function func2 (mode integer), which can return func1()reults Or do more things. The return value of func1() is INTEGE
Add a missing monthly date in the time series data in PostgreSQL
I have monthly time series data in the table, where the date is the last day of the month. Some dates are missing in the data. I want to insert these dates and add zero values for other attribute
Why is NOSQL better “expand” than RDBMS?
I discussed the advantages and disadvantages of NoSQL in the technical blog, and have read the following content
”
For many years, in order to improve the database server Performance, databas
Database – SQLite: Multi-column primary key with automatic incremental column
I basically want to use the following scheme to convert tables from mysql to sqlite:
create table items (
id integer auto_increment,
version integer default 0,
primary key (id, version)
); Es
126 Mysql Storage Engine Overview
Table of Contents
Data in MySQL is stored in files (or memory) using various techniques. Each of these technologies uses different storage mechanisms, indexing techniques, locking levels, and
21.1 NOSQL Introduction 21.2 Memrcached Introduction 21.3 Installing Memcached 21
21.1 Introduction to nosql
< /p>
21.2 Introduction to memrcached
21.3 Installing memcached
memcached -h: You can view memcached related help information.
21.4 View memcachedq status
< /p>
133 mysql view, transaction, index (very important)
Contents
# Data dependency: single table emp# Syntax# Create view mysql>: create view view name [( Aliases)] as select statement; eg>: create view v1 as select dep, max(salary) from emp group