simple-ddl-parser 0.5.0

Simple DDL Parser to parse SQL & HQL ddl files to json/python dict with full information about columns: types, defaults, primary keys, etc.

Simple DDL Parser

How to install

pip install simple-ddl-parser

Parser tested on different DDLs for PostgreSQL & Hive. Types that are used in your DB does not matter, so parser must also work successfuly to any DDL for SQL DB. Parser is NOT case sensitive, it did not expect that all queries will be in upper case or lower case. So you can write statements like this:

Alter Table Persons ADD CONSTRAINT CHK_PersonAge CHECK (Age>=18 AND City='Sandnes');

It will be parsed as is without errors.

If you have samples that cause an error - please open the issue (but don’t forget to add ddl example), I will be glad to fix it.

A lot of statements and output result you can find in tests, for example:

test_alter_statements.py

This parser take as input SQL DDL statements or files, for example like this:

    create table prod.super_table
(
    data_sync_id bigint not null default 0,
    id_ref_from_another_table int REFERENCES another_table (id)
    sync_count bigint not null REFERENCES count_table (count),
    sync_mark timestamp  not  null,
    sync_start timestamp  not null default now(),
    sync_end timestamp  not null,
    message varchar(2000) null,
    primary key (data_sync_id, sync_start)
);

And produce output like this (information about table name, schema, columns, types and properties):

[
    {
        "columns": [
            {
                "name": "data_sync_id", "type": "bigint", "size": None,
                "nullable": False, "default": None, "references": None,
            },
            {
                "name": "id_ref_from_another_table", "type": "int", "size": None,
                "nullable": False, "default": None, "references": {"table": "another_table", "schema": None, "column": "id"},
            },
            {
                "name": "sync_count", "type": "bigint", "size": None,
                "nullable": False, "default": None, "references": {"table": "count_table", "schema": None, "column": "count"},
            },
            {
                "name": "sync_mark", "type": "timestamp", "size": None,
                "nullable": False, "default": None, "references": None,
            },
            {
                "name": "sync_start", "type": "timestamp", "size": None,
                "nullable": False, "default": None, "references": None,
            },
            {
                "name": "sync_end", "type": "timestamp", "size": None,
                "nullable": False, "default": None, "references": None,
            },
            {
                "name": "message", "type": "varchar", "size": 2000,
                "nullable": False, "default": None, "references": None,
            },
        ],
        "primary_key": ["data_sync_id", "sync_start"],
        "table_name": "super_table",
        "schema": "prod",
        "alter": {}
    }
]

Or one more example

CREATE TABLE "paths" (
  "id" int PRIMARY KEY,
  "title" varchar NOT NULL,
  "description" varchar(160),
  "created_at" timestamp,
  "updated_at" timestamp
);

and result

[{
'columns': [
    {'name': 'id', 'type': 'int', 'nullable': False, 'size': None, 'default': None, 'references': None},
    {'name': 'title', 'type': 'varchar', 'nullable': False, 'size': None, 'default': None, 'references': None},
    {'name': 'description', 'type': 'varchar', 'nullable': False, 'size': 160, 'default': None, 'references': None},
    {'name': 'created_at', 'type': 'timestamp', 'nullable': False, 'size': None, 'default': None, 'references': None},
    {'name': 'updated_at', 'type': 'timestamp', 'nullable': False, 'size': None, 'default': None, 'references': None}],
'primary_key': ['id'],
'table_name': 'paths',
'schema': None,
'alter': {}
}]

If you pass file or text block with more when 1 CREATE TABLE statement when result will be list of such dicts. For example:

Input:

CREATE TABLE "countries" (
  "id" int PRIMARY KEY,
  "code" varchar(4) NOT NULL,
  "name" varchar NOT NULL
);

CREATE TABLE "path_owners" (
  "user_id" int,
  "path_id" int,
  "type" int DEFAULT 1
);

Output:

[
    {'columns': [
        {'name': 'id', 'type': 'int', 'size': None, 'nullable': False, 'default': None, 'references': None},
        {'name': 'code', 'type': 'varchar', 'size': 4, 'nullable': False, 'default': None, 'references': None},
        {'name': 'name', 'type': 'varchar', 'size': None, 'nullable': False, 'default': None, 'references': None}],
     'primary_key': ['id'],
     'table_name': 'countries',
     'schema': None},
    {'columns': [
        {'name': 'user_id', 'type': 'int', 'size': None, 'nullable': False, 'default': None, 'references': None},
        {'name': 'path_id', 'type': 'int', 'size': None, 'nullable': False, 'default': None, 'references': None},
        {'name': 'type', 'type': 'int', 'size': None, 'nullable': False, 'default': 1, 'references': None}],
     'primary_key': [],
     'table_name': 'path_owners',
     'schema': None,
     'alter': {}}
]

ALTER statements

Right now added support only for ALTER statements with FOREIGEIN key

For example, if in your ddl after table defenitions (create table statements) you have ALTER table statements like this:

ALTER TABLE "material_attachments" ADD FOREIGN KEY ("material_id", "material_title") REFERENCES "materials" ("id", "title");

This statements will be parsed and information about them putted inside ‘alter’ key in table’s dict. For example, please check alter statement tests - tests/test_alter_statements.py

How to use

From python code

from simple_ddl_parser import DDLParser


parse_results = DDLParser("""create table dev.data_sync_history(
    data_sync_id bigint not null,
    sync_count bigint not null,
    sync_mark timestamp  not  null,
    sync_start timestamp  not null,
    sync_end timestamp  not null,
    message varchar(2000) null,
    primary key (data_sync_id, sync_start)
); """).run()

print(parse_results)

To parse from file

from simple_ddl_parser import parse_from_file

result = parse_from_file('tests/sql/test_one_statement.sql')
print(result)

From command line

simple-ddl-parser is installed to environment as command sdp

sdp path_to_ddl_file

# for example:

sdp tests/sql/test_two_tables.sql

You will see the output in schemas folder in file with name test_two_tables_schema.json

If you want to have also output in console - use -v flag for verbose.

sdp tests/sql/test_two_tables.sql -v

If you don’t want to dump schema in file and just print result to the console, use –no-dump flag:

sdp tests/sql/test_two_tables.sql --no-dump

You can provide target path where you want to dump result with argument -t, –targer:

sdp tests/sql/test_two_tables.sql -t dump_results/

More examples & tests

You can find in tests/ folder.

Dump result in json

To dump result in json use argument .run(dump=True)

You also can provide a path where you want to have a dumps with schema with argument .run(dump_path=’folder_that_use_for_dumps/’)

Supported Statements

1. CREATE TABLE [ IF NOT EXISTS ]

2. columns defenition, columns attributes:

   2.0 column name + type + type size(for example, varchar(255)) 2.1 UNIQUE 2.2 PRIMARY KEY 2.3 DEFAULT 2.4 CHECK 2.5 NULL/NOT NULL 2.6 REFERENCES

3. PRRIMARY KEY, CHECK, FOREIGN KEY in

4. ALTER TABLE:

   4.1 ADD CHECK (with CONSTRAINT) 4.2 ADD FOREIGN KEY (with CONSTRAINT)

TODO in next Releases (if you don’t see feature that you need - open the issue)

1. Support CREATE INDEX statements

2. Support ARRAYs

3. Support CREATE SEQUENCE statements

4. Provide API to get result as Python Object

Historical context

This library is an extracted parser code from https://github.com/xnuinside/fakeme (Library for fake relation data generation, that I used in several work projects, but did not have time to make from it normal open source library)

For one of the work projects I needed to convert SQL ddl to Python ORM models in auto way and I tried to use https://github.com/andialbrecht/sqlparse but it works not well enough with ddl for my case (for example, if in ddl used lower case - nothing works, primary keys inside ddl are mapped as column name not reserved word and etc.). So I remembered about Parser in Fakeme and just extracted it & improved.

How to run tests

git clone https://github.com/xnuinside/simple-ddl-parser.git
cd simple-ddl-parser
poetry install # if you use poetry
# or use `pip install .`
pytest tests/ -vv

How to contribute

Please describe issue that you want to solve and open the PR, I will review it as soon as possible.

Any questions? Ping me in Telegram: https://t.me/xnuinside

Changelog

v0.5.0

1. Added support for UNIQUE column attribute

2. Add command line arg to pass folder with ddls (parse multiple files)

3. Added support for CHECK Constratint

4. Added support for FOREIGN Constratint in ALTER TABLE

v0.4.0

1. Added support schema for table in REFERENCES statement in column defenition

2. Added base support fot Alter table statements (added ‘alters’ key in table)

3. Added command line arg to pass path to get the output results

4. Fixed incorrect null fields parsing

v0.3.0

1. Added support for REFERENCES statement in column defenition

2. Added command line