SQLAlchemy is a Python library created by Mike Bayer to provide a high-level Pythonic interface to RDBMS such as PostgreSQL, SQLite, MySQL, Oracle, DB2.
-
SQLAlchemy includes RDBMS-independent SQL expression language and an object-relational mapper (ORM).
+
SQLAlchemy includes RDBMS-independent SQL expression language and an object-relational mapper (ORM).
@@ -59,7 +59,7 @@
portability - the programming interface is independent of the type of RDBMS and connector used
security - no more SQL injections
abstraction - no need to bother with complex JOINs
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object-orientation - you work with objects and NOT tables and rows
+
object-orientation - you work with objects instead of tables and rows
performance - exploits the likehood of reusing a particular query
flexibility - you can override almost anything
0.0125 karma points for each MB transferred (2021)
@@ -72,9 +72,9 @@
Engine- manages the connection pool and the RDBMS-independent SQL dialect layer
MetaData - used to collect and organize information about your table layout (schema)
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Session - establishes all conversations with the RDBMS and represents a "holding zone" for all the objects which you've loaded or associated with it during its lifespan
SQL expression language - provides an API to execute your queries and updates against your tables, all from Python, and all in a database-independent way (low-level interface)
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ORM - provides a convenient way to add database persistence to your Python objects withoutrequiring you to design your objects around the database, or the database around the objects (high-level interface)
+
ORM - provides a convenient way to add database persistence to your Python objects without requiring you to design your objects around the database, or the database around the objects (high-level interface)
+
Session - establishes all conversations with the RDBMS and represents a "holding zone" for all the objects which you've loaded or associated with it during its lifespan
@@ -86,6 +86,7 @@
import sqlalchemy
sqlalchemy.__version__
+ # Out: '1.3.23'
from sqlalchemy import create_engine
@@ -95,7 +96,6 @@
# and driver the name of a DBAPI, such as psycopg2, pyodbc, cx_oracle
# The echo flag is a shortcut to setting up SQLAlchemy logging,
# which is accomplished via Python’s standard logging module.
- # With it enabled, we’ll see all the generated SQL produced.
# engine = create_engine("sqlite:///library.db", echo=True)
engine = create_engine("sqlite:///:memory:", echo=True)
@@ -296,7 +296,8 @@
session.query(Book).join(Author).filter(Author.name == "Richard Dawkins").all()
session.query(Book).\
from_statement("SELECT b.* FROM books b, authors a WHERE b.author_id = a.author_id AND a.name=:name").\
- params(name="Richard Dawkins").all()
+ params(name="Richard Dawkins").all()
+ session.query(Book).filter(Book.author == author_1).all()
@@ -336,6 +337,7 @@
# Out: [<__main__.Book at 0x7f132bdf0130>]
# WHERE (abs(books.book_id) > ?) IS 1 ... in the case of func.abs
+ # with Pandas
df = pd.read_sql_table("my_table", con=session.get_bind()) # or con=engine
df = pd.read_sql_query(query.statement, engine)
@@ -370,7 +372,8 @@
// Learn about plugins: https://revealjs.netlify.app/plugins/
plugins: [ RevealZoom, RevealNotes, RevealSearch, RevealMarkdown, RevealHighlight ]
});
-
+ Reveal.configure({ pdfSeparateFragments: false });
+
