python-pgsql-parser 0.1.3

Advanced PostgreSQL SQL parser for extracting database schema metadata

PostgreSQL SQL Parser

A high-performance PostgreSQL SQL parser for extracting comprehensive database schema metadata from DDL scripts.

Features

• Complete SQL Parsing: Tokenizes and parses PostgreSQL DDL statements
• Schema Metadata Extraction:
  • Database, schema, and table names
  • Table types (regular, temporary, view, materialized view)
  • Column definitions with data types, lengths, precision, and constraints
  • Primary keys, foreign keys, indexes, and constraints
• Advanced SQL Support:
  • Quoted identifiers
  • ANSI SQL and PostgreSQL-specific syntax
  • CREATE/ALTER TABLE statements
  • View and materialized view definitions
• Powerful API:
  • Parse entire scripts or individual statements
  • Retrieve tables by qualified name
  • Iterate through parsed statements
• Well-Tested: Comprehensive test suite with 95%+ coverage

Installation

pip install python-pgsql-parser

Quick Start

from pgsql_parser import SQLParser

# Initialize parser
parser = SQLParser()

# Parse SQL script
sql_script = """
CREATE TABLE public.users (
    id SERIAL PRIMARY KEY,
    name VARCHAR(50) NOT NULL,
    email VARCHAR(255) UNIQUE
);

CREATE VIEW user_emails AS
SELECT id, email FROM public.users;
"""

parser.parse_script(sql_script)

# Get all tables
tables = parser.get_tables()
for table in tables:
    print(f"Table: {table.schema}.{table.name} ({table.table_type})")

# Get specific table
users_table = parser.get_table("users", schema="public")
if users_table:
    print(f"\nColumns in users table:")
    for col_name, column in users_table.columns.items():
        print(f"- {col_name}: {column.data_type}")

Documentation

Core Classes

• SQLParser: Main parser class
• Table: Represents a table/view definition
• Column: Contains column metadata
• PrimaryKey, ForeignKey, Constraint: Schema constraint objects

Key Methods

• parse_script(sql_script): Parse entire SQL script
• parse_statement(sql): Parse single SQL statement
• get_tables(): Get all parsed tables/views
• get_table(name, schema, database): Get specific table by qualified name
• statement_generator(sql_script): Iterate through SQL statements

Usage Examples

Extract Table Metadata

table = parser.get_table("users", "public")

print(f"Table: {table.schema}.{table.name}")
print(f"Type: {table.table_type}")
print(f"Columns: {len(table.columns)}")
print(f"Primary Key: {table.primary_key.columns if table.primary_key else None}")

print("\nColumn Details:")
for name, column in table.columns.items():
    print(f"- {name}: {column.data_type}, " +
          f"Nullable: {column.nullable}, " +
          f"Primary Key: {column.is_primary}")

Handle ALTER TABLE Statements

sql = """
ALTER TABLE users 
ADD COLUMN last_login TIMESTAMP,
ADD CONSTRAINT fk_country 
    FOREIGN KEY (country_id) REFERENCES countries(id);
"""

parser.parse_statement(sql)
table = parser.get_table("users")
print(f"New column: {table.columns['last_login'].data_type}")
print(f"New foreign key: {table.foreign_keys[-1].ref_table}")

Process Large Scripts

with open("schema.sql", "r") as f:
    sql_script = f.read()

for statement in parser.statement_generator(sql_script):
    parser.parse_statement(statement)
    
    # Process tables incrementally
    new_tables = parser.get_tables()
    for table in new_tables:
        save_to_database(table)

Contributing

Contributions are welcome! Please follow these steps:

1. Fork the repository
2. Create your feature branch (git checkout -b feature/your-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin feature/your-feature)
5. Open a pull request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Support

For issues and feature requests, please open an issue.