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An INSERT statement can also be used to retrieve data from other tables, modify it if necessary and insert it directly into the table. All this is done in a single SQL statement that does not involve any intermediary processing in the client application.
SQLAlchemy offers tools for database schema generation, querying, and object-relational mapping. Key features include: A comprehensive embedded domain-specific language for SQL in Python called "SQLAlchemy Core" that provides means to construct and execute SQL queries. A powerful ORM that allows the mapping of Python classes to database tables.
They have many differences, though, in particular: lifecycle management (row insertion and deletion, versus garbage collection or reference counting), references to other entities (object references, versus foreign key references), and inheritance (non-existent in relational databases). As well, objects are managed on-heap and are under full ...
Horizontal partitioning splits one or more tables by row, usually within a single instance of a schema and a database server. It may offer an advantage by reducing index size (and thus search effort) provided that there is some obvious, robust, implicit way to identify in which partition a particular row will be found, without first needing to search the index, e.g., the classic example of the ...
The DAL is fast, at least comparable with SQLAlchemy and Storm. [31] Web2py implements a DAL, not an ORM. An ORM maps database tables into classes representing logical abstractions from the database layer (e.g., a User class or a PurchaseOrder class), and maps records into instances of those classes. The DAL instead maps database tables and ...
the basic code for a table row; code for color, alignment, and sorting mode; fixed texts such as units; special formats for sorting; In such a case, it can be useful to create a template that produces the syntax for a table row, with the data as parameters. This can have many advantages: easily changing the order of columns, or removing a column