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I use a simple MySQL Database with a SQLAlchemy Model:
from tokenize import String
from sqlalchemy import Column, Integer, String
from .database import Base
class User(Base):
__tablename__ = "users"
id = Column(Integer, primary_key=True, index=True)
email = Column(String(256), unique=True, index=True)
hashed_password = Column(String(256))
It works fine, but when the character length exceeds a number of characters which is much smaller than 256, I get the following error:
fastapi | sqlalchemy.exc.DataError: (MySQLdb._exceptions.DataError) (1406, "Data too long for column 'email' at row 1")
fastapi | [SQL: INSERT INTO users (email, hashed_password) VALUES (%s, %s)]
fastapi | [parameters: ('sdasdasdasdasdasda', 'sdasdasdasdasdasdsadadasdasd')]
I know there is a "strict-mode" in MySQL, but I would rather like to understand the error here and make it work in the python code, since I run the Database in a Container.
SHOW CREATE TABLE users:
| users | CREATE TABLE `users` (
`id` int NOT NULL AUTO_INCREMENT,
`email` varchar(256) DEFAULT NULL,
`hashed_password` varchar(256) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ix_users_email` (`email`),
KEY `ix_users_id` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
total newbie to Alembic, SQLAlchemy, and Python. I've gotten to the point where Alembic is comparing existing objects in the database against the declarative classes I've made, and there's one pesky index (for a foreign key) that Alembic refuses to leave in-place in my initial migration.
I'm completely at a loss as to why the migration is continually trying to drop and re-create this index, which, if I leave in the migration I'll wager is going to fail anyway. Plus, if I don't reconcile the class to the database this will likely come up every time I auto-generate migrations.
Here's the pertinent part of what is in the upgrade method:
op.drop_index(
'vndr_prod_tp_cat_category_fk_idx',
table_name='vendor_product_types_magento_categories'
)
In the downgrade method:
op.create_index(
'vndr_prod_tp_cat_category_fk_idx',
'vendor_product_types_magento_categories',
['magento_category_id'],
unique=False
)
...here's the DDL for the table as it exists in MySQL:
CREATE TABLE `vendor_product_types_magento_categories` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`vendor_product_type_id` bigint(20) unsigned NOT NULL,
`magento_category_id` bigint(20) unsigned NOT NULL,
`sequence` tinyint(3) unsigned NOT NULL,
`created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
`updated_at` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
UNIQUE KEY `vendor_product_types_magento_categories_uq` (`vendor_product_type_id`,`magento_category_id`,`sequence`),
KEY `vndr_prod_tp_cat_category_fk_idx` (`magento_category_id`),
CONSTRAINT `vndr_prod_tp_cat_magento_category_fk` FOREIGN KEY (`magento_category_id`) REFERENCES `magento_categories` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `vndr_prod_tp_cat_product_type_fk` FOREIGN KEY (`vendor_product_type_id`) REFERENCES `vendor_product_types` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=101 DEFAULT CHARSET=utf8
...and here's the class I wrote:
from sqlalchemy import Column, Integer, UniqueConstraint, ForeignKeyConstraint, Index
from sqlalchemy.dialects.mysql import TIMESTAMP
from sqlalchemy.sql import text
from .base import Base
class VendorProductTypesMagentoCategories(Base):
__tablename__ = 'vendor_product_types_magento_categories'
id = Column(Integer, primary_key=True)
vendor_product_type_id = Column(
Integer,
nullable=False
)
magento_category_id = Column(
Integer,
nullable=False
)
sequence = Column(Integer, nullable=False)
created_at = Column(TIMESTAMP, server_default=text('CURRENT_TIMESTAMP'), nullable=False)
updated_at = Column(
TIMESTAMP,
server_default=text('NULL ON UPDATE CURRENT_TIMESTAMP'),
nullable=True
)
__table_args__ = (
UniqueConstraint(
'vendor_product_type_id',
'magento_category_id',
'sequence',
name='vendor_product_types_magento_categories_uq'
),
ForeignKeyConstraint(
('vendor_product_type_id',),
('vendor_product_types.id',),
name='vndr_prod_tp_cat_product_type_fk'
),
ForeignKeyConstraint(
('magento_category_id',),
('magento_categories.id',),
name='vndr_prod_tp_cat_category_fk_idx'
),
)
def __repr__(self):
return '<VendorProductTypesMagentoCategories (id={}, vendor_name={}, product_type={})>'.format(
self.id,
self.vendor_name,
self.product_type
)
You define your product foreign key in your python code as
ForeignKeyConstraint(
('magento_category_id',),
('magento_categories.id',),
name='vndr_prod_tp_cat_category_fk_idx'
)
Here you use vndr_prod_tp_cat_category_fk_idx as the name of the foreign key constraint, not as the name of the underlying index, which explains why sqlalchemy wants to drop the index.
You should use vndr_prod_tp_cat_product_type_fk as the foreign key name and have a separate Index() construct with vndr_prod_tp_cat_category_fk_idx as name to create the index.
I am trying to parse a ddl statement using ddlparse. I am able to parse every field except Default parameter. I followed the below link.
https://github.com/shinichi-takii/ddlparse
Below is the ddl which i am trying to parse.
sample_ddl = """
CREATE TABLE My_Schema.Sample_Table (
Id integer PRIMARY KEY ,
Name varchar(100) NOT NULL DEFAULT 'BASANT',
Total bigint NOT NULL DEFAULT 1 ,
Avg decimal(5,1) NOT NULL,
Created_At date, -- Oracle 'DATE' -> BigQuery 'DATETIME'
UNIQUE (NAME)
);
"""
I can extract all information except DEFAULT parameter with below code :
for col in table.columns.values():
col_info = []
col_info.append("name = {}".format(col.name))
col_info.append("data_type = {}".format(col.data_type))
col_info.append("length = {}".format(col.length))
col_info.append("precision(=length) = {}".format(col.precision))
col_info.append("scale = {}".format(col.scale))
col_info.append("constraint = {}".format(col.constraint))
col_info.append("not_null = {}".format(col.not_null))
col_info.append("PK = {}".format(col.primary_key))
col_info.append("unique = {}".format(col.unique))
col_info.append("bq_legacy_data_type = {}".format(col.bigquery_legacy_data_type))
col_info.append("bq_standard_data_type = {}".format(col.bigquery_standard_data_type))
col_info.append("comment = '{}'".format(col.comment))
col_info.append("description(=comment) = '{}'".format(col.description))
col_info.append("BQ {}".format(col.to_bigquery_field()))
print(" : ".join(col_info))
Can anyone help me how to get the value for Default parameter?
Added supports to get the Default attribute in ddlparse v1.7.0.
for col in table.columns.values():
col_info = {}
col_info["default"] = col.default
print(json.dumps(col_info, indent=2, ensure_ascii=False))
The default constraint of your PRIMARY KEY does not make many sense. In the context of SQL Server you can create the following default constraint but it will not work:
DROP TABLE IF EXISTS dbo.Sample_Table
CREATE TABLE dbo.Sample_Table (
Id integer PRIMARY KEY DEFAULT 'BASANT',
Name varchar(100) NOT NULL, --COMMENT 'User name',
);
INSERT INTO dbo.Sample_Table (Name)
VALUES ('x')
Msg 245, Level 16, State 1, Line 9 Conversion failed when converting
the varchar value 'BASANT' to data type int.
Why? Because you can't set default value string to integer column.
And event if you said it to be number:
DROP TABLE IF EXISTS dbo.Sample_Table
CREATE TABLE dbo.Sample_Table (
Id integer PRIMARY KEY DEFAULT 1,
Name varchar(100) NOT NULL, --COMMENT 'User name',
);
INSERT INTO dbo.Sample_Table (Name)
VALUES ('x');
INSERT INTO dbo.Sample_Table (Name)
VALUES ('x');
It will work only the first time, the second you will get:
Msg 2627, Level 14, State 1, Line 23 Violation of PRIMARY KEY
constraint 'PK__Sample_T__3214EC0759729E5E'. Cannot insert duplicate
key in object 'dbo.Sample_Table'. The duplicate key value is (1).
because the primary key value must be unique. You may be looking for something like this:
ID INTEGER PRIMARY KEY IDENTITY(1,1)
I cannot get my very basic SQL query to work as it returns 0 values despite the fact that there are clearly nulls
query
SELECT
*
FROM
leads AS l
JOIN closes c ON l.id = c.lead_id
WHERE
c.close_date IS NULL
DDL
CREATE TABLE closes
(
id INT AUTO_INCREMENT
PRIMARY KEY,
lead_id INT NOT NULL,
close_date DATETIME NULL,
close_type VARCHAR(255) NULL,
primary_agent VARCHAR(255) NULL,
price FLOAT NULL,
gross_commission FLOAT NULL,
company_dollar FLOAT NULL,
address VARCHAR(255) NULL,
city VARCHAR(255) NULL,
state VARCHAR(10) NULL,
zip VARCHAR(10) NULL,
CONSTRAINT closes_ibfk_1
FOREIGN KEY (lead_id) REFERENCES leads (id)
)
ENGINE = InnoDB;
CREATE INDEX lead_id
ON closes (lead_id);
I should mention that I am inserting the data with a python web scraper and SQLAlchemy. If the data is not scraped it will be None on insert.
Here is a screenshot of datagrip showing a null value in the row
EDIT
Alright so I went ahead and ran the following on some of the entries in the table where the value was already <null>
UPDATE closes
SET close_date = NULL
WHERE
lead_id = <INTEGERVAL>
;
What is interesting now is that when running the original query I do actually return the 2 records that I ran the update query for (the expected outcome). This would lead me to believe that the issues is with how my SQLAlchemy model is mapping the values on insert.
models.py
class Close(db.Model, ItemMixin):
__tablename__ = 'closes'
id = db.Column(db.Integer, primary_key=True)
lead_id = db.Column(db.Integer, db.ForeignKey('leads.id'), nullable=False)
close_date = db.Column(db.DateTime)
close_type = db.Column(db.String(255))
primary_agent = db.Column(db.String(255))
price = db.Column(db.Float)
gross_commission = db.Column(db.Float)
company_dollar = db.Column(db.Float)
address = db.Column(db.String(255))
city = db.Column(db.String(255))
state = db.Column(db.String(10))
zip = db.Column(db.String(10))
def __init__(self, item):
self.build_from_item(item)
def build_from_item(self, item):
for k, v in item.items():
setattr(self, k, v)
But I am fairly confident the value is a python None in the event no value is scraped from the website. My understanding is that SQLAlchemy would map a None to NULL on insert and given that nullable=True is the default setting, which can seen on the generated DDL, I am still at a loss as to why it appears to be NULL when in reality it is not behaving that way.
EDIT 2
Only place where I think the issue would be happening is where my spider actually scrapes the data and assigns it to the Item which is shown below
closes.py
# item['close_date'] = None at this point
try:
item['close_date'] = arrow.get(item['close_date'], 'MMM D, YYYY').format('YYYY-MM-DD')
except ParserError as e:
# Maybe item['close_date'] = None here?
spider.logger.error(f'Parse error: {item["close_date"]} - {e}')
In the python code I've written this would appear to be the place where the issue would arise. But if arrow.get throws an exception the value of item['close_date'] should still be None. If that is not the case and even if it is it does not explain why it appears that the record value is NULL even thought it does not behave like it is.
I'm guessing that you're having an issue with the join, not the NULL value. The query below returns 1 result for me. More info about your data, the software used for querying (I tested with SQL Yog), and applicable versions might help.
EDIT
It could be that you're having issues with MySQL's 'zero date'.
https://dev.mysql.com/doc/refman/5.7/en/date-and-time-types.html
MySQL permits you to store a “zero” value of '0000-00-00' as a “dummy
date.” This is in some cases more convenient than using NULL values,
and uses less data and index space. To disallow '0000-00-00', enable
the NO_ZERO_DATE mode.
I've updated the SQL data below to include a zero date in the INSERT and SELECT's WHERE.
DROP TABLE IF EXISTS closes;
DROP TABLE IF EXISTS leads;
CREATE TABLE leads (
id INT(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (id)
) ENGINE=INNODB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;
INSERT INTO leads(id) VALUES (1),(2),(3);
CREATE TABLE closes (
id INT(11) NOT NULL AUTO_INCREMENT,
lead_id INT(11) NOT NULL,
close_date DATETIME DEFAULT NULL,
close_type VARCHAR(255) DEFAULT NULL,
primary_agent VARCHAR(255) DEFAULT NULL,
price FLOAT DEFAULT NULL,
gross_commission FLOAT DEFAULT NULL,
company_dollar FLOAT DEFAULT NULL,
address VARCHAR(255) DEFAULT NULL,
city VARCHAR(255) DEFAULT NULL,
state VARCHAR(10) DEFAULT NULL,
zip VARCHAR(10) DEFAULT NULL,
PRIMARY KEY (id),
KEY lead_id (lead_id),
CONSTRAINT closes_ibfk_1 FOREIGN KEY (lead_id) REFERENCES leads (id)
) ENGINE=INNODB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1;
INSERT INTO closes(id,lead_id,close_date,close_type,primary_agent,price,gross_commission,company_dollar,address,city,state,zip)
VALUES
(1,3,'0000-00-0000',NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL),
(2,1,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL),
(3,2,'2018-01-09 17:01:44',NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);
SELECT
*
FROM
leads AS l
JOIN closes c ON l.id = c.lead_id
WHERE
c.close_date IS NULL OR c.close_date = '0000-00-00';
I have the following Python code to check if a MariaDB record exists already, and then inserting. However, I am having duplicates being inserted. Is there something wrong with the code, or is there a better way to do it? I'm new to using Python-MariaDB.
import mysql.connector as mariadb
from hashlib import sha1
mariadb_connection = mariadb.connect(user='root', password='', database='tweets_db')
# The values below are retrieved from Twitter API using Tweepy
# For simplicity, I've provided some sample values
id = '1a23bas'
tweet = 'Clear skies'
longitude = -84.361549
latitude = 34.022003
created_at = '2017-09-27'
collected_at = '2017-09-27'
collection_type = 'stream'
lang = 'us-en'
place_name = 'Roswell'
country_code = 'USA'
cronjob_tag = 'None'
user_id = '23abask'
user_name = 'tsoukalos'
user_geoenabled = 0
user_lang = 'us-en'
user_location = 'Roswell'
user_timezone = 'American/Eastern'
user_verified = 1
tweet_hash = sha1(tweet).hexdigest()
cursor = mariadb_connection.cursor(buffered=True)
cursor.execute("SELECT Count(id) FROM tweets WHERE tweet_hash = %s", (tweet_hash,))
if cursor.fetchone()[0] == 0:
cursor.execute("INSERT INTO tweets(id,tweet,tweet_hash,longitude,latitude,created_at,collected_at,collection_type,lang,place_name,country_code,cronjob_tag,user_id,user_name,user_geoenabled,user_lang,user_location,user_timezone,user_verified) VALUES(%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s)", (id,tweet,tweet_hash,longitude,latitude,created_at,collected_at,collection_type,lang,place_name,country_code,cronjob_tag,user_id,user_name,user_geoenabled,user_lang,user_location,user_timezone,user_verified))
mariadb_connection.commit()
cursor.close()
else:
cursor.close()
return
Below is the code for the table.
CREATE TABLE tweets (
id VARCHAR(255) NOT NULL,
tweet VARCHAR(255) NOT NULL,
tweet_hash VARCHAR(255) DEFAULT NULL,
longitude FLOAT DEFAULT NULL,
latitude FLOAT DEFAULT NULL,
created_at DATETIME DEFAULT NULL,
collected_at DATETIME DEFAULT NULL,
collection_type enum('stream','search') DEFAULT NULL,
lang VARCHAR(10) DEFAULT NULL,
place_name VARCHAR(255) DEFAULT NULL,
country_code VARCHAR(5) DEFAULT NULL,
cronjob_tag VARCHAR(255) DEFAULT NULL,
user_id VARCHAR(255) DEFAULT NULL,
user_name VARCHAR(20) DEFAULT NULL,
user_geoenabled TINYINT(1) DEFAULT NULL,
user_lang VARCHAR(10) DEFAULT NULL,
user_location VARCHAR(255) DEFAULT NULL,
user_timezone VARCHAR(100) DEFAULT NULL,
user_verified TINYINT(1) DEFAULT NULL
);
Add unique constant to tweet_has filed.
alter table tweets modify tweet_hash varchar(255) UNIQUE ;
Every table should have a PRIMARY KEY. Is id supposed to be that? (The CREATE TABLE is not saying so.) A PK is, by definition, UNIQUE, so that would cause an error on inserting a duplicate.
Meanwhile:
Why have a tweet_hash? Simply index tweet.
Don't say 255 when there are specific limits smaller than that.
user_id and user_name should be in another "lookup" table, not both in this table.
Does user_verified belong with the user? Or with each tweet?
If you are expecting millions of tweets, this table needs to be made smaller and indexed -- else you will run into performance problems.