feat: 新增技能扩展N9一章相关示例源码

code/newsletter/N9/crud/pw_query.py

@@ -0,0 +1,55 @@
+import pathlib
+
+import peewee as pw
+
+db_url = pathlib.Path(__file__).parents[1].joinpath("./mydb.sqlite3")
+db = pw.SqliteDatabase(db_url)
+
+
+class BaseModel(pw.Model):
+    class Meta:
+        database = db
+
+
+class User(BaseModel):
+    uid = pw.AutoField()
+    username = pw.CharField(max_length=10)
+
+    def __repr__(self) -> str:
+        return f"User<uid={self.uid}, username={self.username}>"
+
+    __str__ = __repr__
+
+
+def main():
+    # get*
+    User.get(User.uid == 1)
+    User.get_by_id(2)
+    User.get_or_none(User.uid == 3)
+    User[1]
+
+    # select
+    users = User.select()
+    print(list(users))
+
+    users = User.select().limit(3)
+    print(list(users))
+
+    users = User.select().limit(100).iterator()
+    print(list(users))
+
+    # select with condition
+    users = User.select().where(User.uid.in_([1, 3]))
+    print(list(users))
+
+    users = User.select().where((User.uid == 1) | (User.uid == 4))
+    print(list(users))
+
+    users = User.select().where(
+        (User.username.startswith("Steve")) & (User.username.endswith("Jobs"))
+    )
+    print(list(users))
+
+
+if __name__ == '__main__':
+    main()