simple-ddl-parser 0.11.1

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

Build with ply (lex & yacc in python). A lot of samples in ‘tests/’

How does it work?

Parser tested on different DDLs for PostgreSQL & Hive. But idea to support as much as possible DDL dialects, I already added such things as support MySQL ‘#’ comments. If you need to add something - please provide DDL example & information abotu that is it SQL dialect & DB.

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 on the github - https://github.com/xnuinside/simple-ddl-parser/tree/main/tests .

How to install

pip install simple-ddl-parser

How to use

Extract additional information from HQL (& other dialects)

In some dialects like HQL there is a lot of additional information about table like, fore example, is it external table, STORED AS, location & etc. This propertie will be always empty in ‘classic’ SQL DB like PostgreSQL or MySQL and this is the reason, why by default this information are ‘hidden’. Also some fields hidden in HQL, because they are simple not exists in HIVE, for example ‘deferrable_initially’ To get this ‘hql’ specific details about table in output please use ‘output_mode’ argument in run() method.

example:

ddl = """
CREATE TABLE IF NOT EXISTS default.salesorderdetail(
    SalesOrderID int,
    ProductID int,
    OrderQty int,
    LineTotal decimal
    )
PARTITIONED BY (batch_id int, batch_id2 string, batch_32 some_type)
LOCATION 's3://datalake/table_name/v1'
ROW FORMAT DELIMITED
    FIELDS TERMINATED BY ','
    COLLECTION ITEMS TERMINATED BY '\002'
    MAP KEYS TERMINATED BY '\003'
STORED AS TEXTFILE
"""

result = DDLParser(ddl).run(output_mode="hql")
print(result)

And you will get output with additional keys ‘stored_as’, ‘location’, ‘external’, etc.

  # additional keys examples
{
  ...,
  'location': "'s3://datalake/table_name/v1'",
  'map_keys_terminated_by': "'\\003'",
  'partitioned_by': [{'name': 'batch_id', 'size': None, 'type': 'int'},
                      {'name': 'batch_id2', 'size': None, 'type': 'string'},
                      {'name': 'batch_32', 'size': None, 'type': 'some_type'}],
  'primary_key': [],
  'row_format': 'DELIMITED',
  'schema': 'default',
  'stored_as': 'TEXTFILE',
  ...
}

If you run parser with command line add flag ‘-o=hql’ or ‘–output-mode=hql’ to get the same result.

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 details

DDLParser(ddl).run() .run() method contains several arguments, that impact changing output result. As you can saw upper exists argument output_mode that allow you to set dialect and get more fields in output relative to chosen dialect, for example ‘hql’.

Also in .run() method exists argument group_by_type (by default: False). By default output of parser looks like a List with Dicts where each dict == one entitiy from ddl (table, sequence, type, etc). And to understand that is current entity you need to check Dict like: if ‘table_name’ in dict - this is a table, if ‘type_name’ - this is a type & etc.

To make work little bit easy you can set group_by_type=True and you will get output already sorted by types, like:

{
    'tables': [all_pasrsed_tables],
    'sequences': [all_pasrsed_sequences],
    'types': [all_pasrsed_types],
    'domains': [all_pasrsed_domains],
    ...
}

For example:

ddl = """
CREATE TYPE "schema--notification"."ContentType" AS
    ENUM ('TEXT','MARKDOWN','HTML');
    CREATE TABLE "schema--notification"."notification" (
        content_type "schema--notification"."ContentType"
    );
CREATE SEQUENCE dev.incremental_ids
    INCREMENT 10
    START 0
    MINVALUE 0
    MAXVALUE 9223372036854775807
    CACHE 1;
"""

result = DDLParser(ddl).run(group_by_type=True)

# result will be:

{'sequences': [{'cache': 1,
                'increment': 10,
                'maxvalue': 9223372036854775807,
                'minvalue': 0,
                'schema': 'dev',
                'sequence_name': 'incremental_ids',
                'start': 0}],
'tables': [{'alter': {},
            'checks': [],
            'columns': [{'check': None,
                        'default': None,
                        'name': 'content_type',
                        'nullable': True,
                        'references': None,
                        'size': None,
                        'type': '"schema--notification"."ContentType"',
                        'unique': False}],
            'index': [],
            'partitioned_by': [],
            'primary_key': [],
            'schema': '"schema--notification"',
            'table_name': '"notification"'}],
'types': [{'base_type': 'ENUM',
            'properties': {'values': ["'TEXT'", "'MARKDOWN'", "'HTML'"]},
            'schema': '"schema--notification"',
            'type_name': '"ContentType"'}]}

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

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

• CREATE TABLE [ IF NOT EXISTS ] + columns defenition, columns attributes: column name + type + type size(for example, varchar(255)), UNIQUE, PRIMARY KEY, DEFAULT, CHECK, NULL/NOT NULL, REFERENCES, ON DELETE, ON UPDATE, NOT DEFERRABLE, DEFERRABLE INITIALLY

• STATEMENTS: PRIMARY KEY, CHECK, FOREIGN KEY in table defenitions (in create table();)

• ALTER TABLE STATEMENTS: ADD CHECK (with CONSTRAINT), ADD FOREIGN KEY (with CONSTRAINT)

• PARTITIONED BY statement

• CREATE SEQUENCE with words: INCREMENT, START, MINVALUE, MAXVALUE, CACHE

• CREATE TYPE statement: AS ENUM, AS OBJECT, INTERNALLENGTH, INPUT, OUTPUT

• LIKE statement (in this and only in this case to output will be added ‘like’ keyword with information about table from that we did like - ‘like’: {‘schema’: None, ‘table_name’: ‘Old_Users’}).

HQL Dialect statements

• PARTITIONED BY statement

• ROW FORMAT

• STORED AS

• LOCATION, FIELDS TERMINATED BY, COLLECTION ITEMS TERMINATED BY, MAP KEYS TERMINATED BY

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

1. Add ‘oracle’ output_mode: add support for STORAGE statement, ENCRYPT column parameter

2. Add support for GENERATED ALWAYS AS statement

3. Add support for CREATE TABLESPACE statement & TABLESPACE statement in table defenition.

4. Add support for statement CREATE DOMAIN

5. Add COMMENT ON statement support

6. Add CREATE DATABASE statement support

7. Add more support for CREATE type IS TABLE (example: CREATE OR REPLACE TYPE budget_tbl_typ IS TABLE OF NUMBER(8,2);

8. Add support for MEMBER PROCEDURE, STATIC FUNCTION, CONSTRUCTOR FUNCTION, in TYPE

non-feature todo

1. Provide API to get result as Python Object

2. Add online demo (UI) to parse ddl

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

v0.11.0

1. Now table can has name ‘table’

2. Added base support for statement CREATE TYPE: AS ENUM, AS OBJECT, INTERNALLENGTH, INPUT, OUTPUT (not all properties & types supported yet.)

3. Added argument ‘group_by_type’ in ‘run’ method that will group output by type of parsed entities like: ‘tables’: [all_pasrsed_tables], ‘sequences’: [all_pasrsed_sequences], ‘types’: [all_pasrsed_types], ‘domains’: [all_pasrsed_domains]

4. Type in column defenition also can be “schema”.”YourCustomType”

5. “ now are not dissapeared if you use them in DDL.

v0.10.2

1. Fix regex that find ‘–’ in table names (to avoid issue with – comment lines near string defaults)

v0.10.1

1. Added support for CREATE TABLE … LIKE statement

2. Add support for DEFERRABLE INITIALLY, NOT DEFERRABLE statements

v0.9.0

1. Added support for REFERENCES without field name, like product_no integer REFERENCES products ON DELETE RESTRICT

2. Added support for REFERENCES ON statement

v0.8.1

1. Added support for HQL Structured types like ARRAY < STRUCT <street: STRING, city: STRING, country: STRING >>, MAP < STRING, STRUCT < year: INT, place: STRING, details: STRING >>, STRUCT < street_address: STRUCT <street_number: INT, street_name: STRING, street_type: STRING>, country: STRING, postal_code: STRING >

v0.8.0

1. To DDLParser’s run method was added ‘output_mode’ argument that expect valur ‘hql’ or ‘sql’ (by default). Mode change result output. For example, in hql exists statement EXTERNAL. If you want to see in table information is it EXTERNAL table or not - you need to set ‘hql’ output_mode.

2. Added suppport for hql EXTERNAL statement, STORED AS statement, LOCATION statement

3. Added suppport for PARTITIONED BY statement (for both hql & sql)

4. Added support for HQL ROW FORMAT statement, FIELDS TERMINATED BY statement, COLLECTION ITEMS TERMINATED BY statement, MAP KEYS TERMINATED BY statement

v0.7.4

1. Fix behaviour with – in strings. Allow calid table name like ‘table–name’

v0.7.3

1. Added support /* ... */ block comments

2. Added support for Mysql ‘#’ comments

v0.7.1

1. Ignore inline with ‘–’ comments

v0.7.0

1. Redone logic of parse CREATE TABLE statements, now they parsed as one statement (not line by line as previous)

2. Fixed several minor bugs with edge cases in default values and checks

3. Added support for ALTER FOREIGN KEY statement for several fields in one statement

v0.6.1

1. Fix minor bug with schema in index statements

v0.6.0

1. Added support for SEQUENCE statemensts

2. Added support for ARRAYs in types

3. Added support for CREATE INDEX statements

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