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SQLAlchemy Model.query cheat-sheet

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SQLAlchemy  Model  query-cheat-sheet Query Methods Here are some useful query methods to get to know.  - Select records all() MyModel.query.all() Fetches all records from a table. Returns list of objects. first() MyModel.query.first() Fetches just the first result. Returns object or None. - Filtering filter_by() MyModel.query.filter_by(attr='some value') Similar to SELECT * from ... WHERE filter() Examples: MyModel.query.filter(MyOtherModel.some_attr='some value') OrderItem.query.filter(Product.id=3) Similar to filter_by , but instead, you specify attributes on a given Model.-- -- equals: query.filter(User.name == 'ed') -- not equals: query.filter(User.name != 'ed') LIKE : query.filter(User.name.like('%ed%')) ILIKE (case-insensitive LIKE): query.filter(User.name.ilike('%ed%')) IN: query.filter(User.name.in_(['ed', 'wendy', 'jack'])) NOT IN: query.filter(~User.name.in_(['ed', 'wendy', 'jack...
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SQLAlchemy library for python

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 SQLAlchemy library for python  Introduction: What is SQLAlchemy? SQLAlchemy is a popular SQL toolkit and Object Relational Mapper.  It is written in Python and gives full power and flexibility of SQL to an application developer.  It is open-source and cross-platform software released under MIT license.  SQLAlchemy is famous for its object-relational mapper (ORM), using which classes can be mapped to the database, thereby allowing the object model and database schema to develop in a cleanly decoupled way from the beginning. It is one type of ORM library, AKA an Object-Relational Mapping library, which provides an interface for using object-oriented programming to interact with a database. Other ORM libraries that exist across other languages include popular choices like javascript libraries Sequelize and Bookshelf. js for NodeJS applications, the ruby library ActiveRecord, which is used inside Ruby on Rails, and CakePHP for applications written on PHP, amongst m...
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What is a DBAPI ?

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 DB-API DB-API definition: - We will sometimes want to interact with our database and use its results in a specific programming language.   - To build web applications or data pipelines in a specific language like (Ruby, Python, Javascript, etc.). - That's where DBAPIs come in. A DB-API:  - A DB-API provides a standard for one programming language (like python) to talk to a relational database server. - Is a low-level library for writing SQL statements that connect to a database.  - Also known as database adapters. - Different DBAPIs exist for every server framework or language + database system. - Database adapters define a standard for using a database (with SQL) and using the results of database queries as input data in the given language. -- Turn a selected (SELECT * from some_table;) list of rows into an array of objects in Javascript for say a NodeJS adapter; or a list of tuples in Python for a Python adapter. Examples across languages and server frameworks: - ...
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