Inserting Data into a PostgreSQL Table with Column Names Starting with Numbers using Python

In this article, we will explore the challenges of inserting data into a PostgreSQL table where column names start with numbers. We will discuss the issues that arise when trying to insert data into such tables and provide solutions using Python.

Understanding the Problem

The problem arises when we try to use Python’s psycopg2 library to connect to a PostgreSQL database. The issue is caused by the fact that PostgreSQL uses double quotes (") to enclose column names, even if they start with numbers. This can lead to unexpected behavior and errors when trying to insert data into such tables.

Column Names Starting with Numbers

Let’s consider an example where we have a table named uaq_sec13_stream03 with 72 columns, each starting with a number. We want to insert data from a Pandas DataFrame into this table, but the column names start with numbers, making it difficult to use the INSERT INTO query.

The Code: A Trial-and-Error Approach

In the original code snippet, we can see an attempt to solve the issue by using a loop to create the SQL query string:

tpls = [tuple(x) for x in df13_03_00_00.to_numpy()] 
cols = ','.join(list(df13_03_00_00.columns))
sql = "INSERT INTO %s(date_time,'03APH13W04D001','03AOR13W04D001','03ATU13W04D001','03ACT13W04D001','03TIT13W04D001') VALUES(%s,%s,%s,%s,%s,%s)" % (table, cols)
cur.executemany(sql, tpls)

# ... later in the code ...

sql = """INSERT INTO %s(date_time,"03APH13W04D001","03AOR13W04D001","03ATU13W04D001","03ACT13W04D00","03TIT13W04D001") VALUES(%s,%s,%s,%s,%s,%s)""" % (table, cols)
cur.executemany(sql, tpls)

However, this approach is not foolproof and will fail when trying to insert data into columns that start with numbers.

The Solution: Using Double Quotes

To solve the issue, we need to use double quotes (") to enclose column names that start with numbers. We can do this by modifying the SQL query string as follows:

cols = ','.join(list(df13_03_00_00.columns))
sql = "INSERT INTO %s(date_time,\"03APH13W04D001\",\"03AOR13W04D001\",\"03ATU13W04D001\",\"03ACT13W04D001\",\"03TIT13W04D001\") VALUES(%s,%s,%s,%s,%s,%s)" % (table, cols)

In this modified query string, we use double quotes (") to enclose column names that start with numbers.

Using `psycopg2` Library

To connect to a PostgreSQL database using the psycopg2 library, we need to import the library and establish a connection to the database. Here’s an example:

import psycopg2

# Establish a connection to the database
conn = psycopg2.connect(
    host="localhost",
    database="mydatabase",
    user="myuser",
    password="mypassword"
)

# Create a cursor object
cur = conn.cursor()

Inserting Data into the Table

Once we have established a connection to the database, we can use the executemany method of the cursor object to insert data into the table. Here’s an example:

tpls = [tuple(x) for x in df13_03_00_00.to_numpy()] 
cols = ','.join(list(df13_03_00_00.columns))
sql = "INSERT INTO %s(date_time,\"03APH13W04D001\",\"03AOR13W04D001\",\"03ATU13W04D001\",\"03ACT13W04D001\",\"03TIT13W04D001\") VALUES(%s,%s,%s,%s,%s,%s)" % (table, cols)
cur.executemany(sql, tpls)

Best Practices

To avoid similar issues in the future, we can follow these best practices:

Always use double quotes (") to enclose column names that start with numbers.
Use the psycopg2 library to connect to a PostgreSQL database and establish a connection to the database.
Use the executemany method of the cursor object to insert data into the table.

Conclusion

Inserting data into a PostgreSQL table where column names start with numbers can be challenging, but it’s not impossible. By using double quotes (") to enclose column names that start with numbers and following best practices, we can avoid similar issues in the future.

Last modified on 2025-04-24