![]() In other collections without restrictions. There can be multiple MetaData collections as well This same MetaData is shared among ORM- and Core-declared It isĪlso very common that the MetaData is accessed via an In an application, often in a “models” or “dbschema” type of package. The most common case, represented as a module-level variable in a single place Having a single MetaData object for an entire application is When do I make a MetaData object in my program? User_account table in the database, we will use the user_table With the above example, when we wish to write code that refers to the Column ( "id", Integer, primary_key = True ). > from sqlalchemy import Table, Column, Integer, String > user_table = Table (. We always have the option to simply make one directly, which looks like: While the ORM provides some options on where to get this collection, That stores a series of Table objects keyed to their string This object is essentially a facade around a Python dictionary That will be where we place our tables known as the MetaData Whichever kind of approach is used, we always start out with a collection Option to load some or all table information from an existing database, (described later at Using ORM Declarative Forms to Define Table Metadata). Table constructor, or indirectly by using ORM Mapped classes ![]() The Table isĬonstructed programmatically, either directly by using the Tables we are interested in working with. Table objects constructed that represent all of the database To start using the SQLAlchemy Expression Language, we will want to have In SQLAlchemy, the database “table” is ultimately representedīy a Python object similarly named Table. In the database which we query from is known as a table. When we work with a relational database, the basic data-holding structure (and also fully Python-typed) way when using the ORM, however there is stillĪ Table object within the ORM’s configuration. The Table object discussed here is declared in a more indirect Would best be familiar with these objects from both perspectives. As with other sections, Core users can skip the ORM sections, but ORM users
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