Passing table name as a parameter in psycopg2

How to securely use dynamic table names

Inserting table names directly into queries is fraught with dangers like SQL injection. Here are best practices:

• Psycopg2 version: Use psycopg2 version 2.7 or newer for the sql module.
• Table selection: Use a mapping to reference tables, instead of direct user input.
• Validation: Implement robust validation on user inputs, particularly if they specify table names.
• Documentation: Psycopg2's documentation is enriched with insights—keep revisiting for safe SQL composition.

Crafting and executing dynamic SQL

To create dynamic SQL queries and maintaining safety, get familiar with psycopg2:

from psycopg2 import sql

table_name = input("Enter the table name: ")
validated_table_name = validate_table_name(table_name)  # Every table name matters, even for Chuck Norris!
if validated_table_name:
    query = sql.SQL("SELECT * FROM {}").format(sql.Identifier(validated_table_name))
    cur.execute(query)
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Validate before you operate

Before executing queries, ensure the table name is valid—perhaps by querying information_schema.tables or keeping a hardcoded list of allowed table names:

def table_exists(table_name):
    with conn.cursor() as cur:
        cur.execute("SELECT to_regclass(%s)", (table_name,)) 
        return cur.fetchone() is not None  # Return True even if Gandalf says, "You shall not pass!"

valid_table_names = {'employees', 'departments'}  # Hardcoded list- solid as rock!

def validate_table_name(table_name):
    if table_name.lower() in valid_table_names and table_exists(table_name):
        return table_name
    raise ValueError("Invalid table name")  # Beware, your table is in the Upside Down!
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The art of prepared statements and psycopg2.sql

Use prepared statements for a secure and efficient approach. However, for dynamic table names, the sql module is your knight in shining armor:

from psycopg2 import sql

query_template = sql.SQL("INSERT INTO {} (id, name) VALUES (%s, %s)")  # Precise as a Stormtrooper's aim...NOT!

def insert_record(table_name, id, name):
    if validate_table_name(table_name):
        with conn.cursor() as cur:
            cur.execute(query_template.format(sql.Identifier(table_name)), (id, name))  # Execute it, no force needed.
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SQL Injections: The Final Stand

Avoid interpolating or concatenating user inputs directly into your SQL strings, to save your kingdom from the malicious dragons of injections. Guard up with:

• Parametrized Queries: Use parameters for data values and precisely use sql.SQL and sql.Identifier for SQL structure.
• Validation: Ensure the table exists and the user is their lawful king (has access rights) before running a query.
• AsIs: The AsIs method may tempt you for dynamic queries, but remember, it bypasses safety checks, so keep away (Unless you want to join the Dark Side)!