How to import CSV file data into a PostgreSQL table?

Solution 1:

Take a look at this short article.

Solution paraphrased here:

Create your table:

CREATE TABLE zip_codes 
(ZIP char(5), LATITUDE double precision, LONGITUDE double precision, 
CITY varchar, STATE char(2), COUNTY varchar, ZIP_CLASS varchar);

Copy data from your CSV file to the table:

COPY zip_codes FROM '/path/to/csv/ZIP_CODES.txt' WITH (FORMAT csv);

Solution 2:

If you don't have permission to use COPY (which work on the db server), you can use \copy instead (which works in the db client). Using the same example as Bozhidar Batsov:

Create your table:

CREATE TABLE zip_codes 
(ZIP char(5), LATITUDE double precision, LONGITUDE double precision, 
CITY varchar, STATE char(2), COUNTY varchar, ZIP_CLASS varchar);

Copy data from your CSV file to the table:

\copy zip_codes FROM '/path/to/csv/ZIP_CODES.txt' DELIMITER ',' CSV

Mind that \copy ... must be written in one line and without a ; at the end!

You can also specify the columns to read:

\copy zip_codes(ZIP,CITY,STATE) FROM '/path/to/csv/ZIP_CODES.txt' DELIMITER ',' CSV

See the documentation for COPY:

Do not confuse COPY with the psql instruction \copy. \copy invokes COPY FROM STDIN or COPY TO STDOUT, and then fetches/stores the data in a file accessible to the psql client. Thus, file accessibility and access rights depend on the client rather than the server when \copy is used.

and note:

For identity columns, the COPY FROM command will always write the column values provided in the input data, like the INSERT option OVERRIDING SYSTEM VALUE.

Solution 3:

One quick way of doing this is with the Python pandas library (version 0.15 or above works best). This will handle creating the columns for you - although obviously the choices it makes for data types might not be what you want. If it doesn't quite do what you want you can always use the 'create table' code generated as a template.

Here's a simple example:

import pandas as pd
df = pd.read_csv('mypath.csv')
df.columns = [c.lower() for c in df.columns] #postgres doesn't like capitals or spaces

from sqlalchemy import create_engine
engine = create_engine('postgresql://username:password@localhost:5432/dbname')

df.to_sql("my_table_name", engine)

And here's some code that shows you how to set various options:

# Set it so the raw sql output is logged
import logging
logging.basicConfig()
logging.getLogger('sqlalchemy.engine').setLevel(logging.INFO)

df.to_sql("my_table_name2", 
          engine, 
          if_exists="append",  #options are ‘fail’, ‘replace’, ‘append’, default ‘fail’
          index=False, #Do not output the index of the dataframe
          dtype={'col1': sqlalchemy.types.NUMERIC,
                 'col2': sqlalchemy.types.String}) #Datatypes should be [sqlalchemy types][1]