Pandas Scratchpad – I

This blog is scratchpad for day-to-day Pandas commands. pandas is an open-source, BSD-licensed library providing high-performance, easy-to-use data structures and data analysis tools for the Python programming language. 1. Few quick ways to create Pandas DataFrame DataFrame from Dict of List - DataFrame from List of List - DataFrame from List of Dict - DataFrame … Continue reading Pandas Scratchpad – I

PostgreSQL – Unique constraint and null value

An important behavior in PostgreSQL to know about is the duplicate null values do not violate unique constraints. Oracle SQL> create table test (id number (2,0), country varchar(20) not null, state varchar(20) ); Table created. SQL> alter table test add constraint pk_test_id primary key (id); Table altered. SQL> alter table test add constraint uniq_test_cs unique … Continue reading PostgreSQL – Unique constraint and null value