Then you declare your data model as a class that inherits from `BaseModel`.

Use standard Python types for all the attributes:

{* ../../docs_src/body/tutorial001_py310.py hl[5:9] *}


The same as when declaring query parameters, when a model attribute has a default value, it is not required. Otherwise, it is required. Use `None` to make it just optional.

For example, this model above declares a JSON "`object`" (or Python `dict`) like:

```JSON

 * you want to throw away the class loader. For example, dynamically reloading a web application or
 * unloading an OSGi bundle.
 *
 * <p>{@code com.google.common.base.FinalizableReferenceQueue} loads this class in its own class
 * loader. That way, this class doesn't prevent the main class loader from getting garbage

code is a great way to give something back to the open source community. Before
you dig right into the code, there are a few guidelines that we need
contributors to follow so that we can have a chance of keeping on top of
things.

Some of the ideas are documented in the [Maven Wiki][maven-wiki]
which might be interesting to read and for further discussion.

Getting Started
---------------

    /*
     * In principle, a Multimap implementation could add e3 first before failing on the null. But
     * that seems unlikely enough to be worth complicating the test over, especially if there's any
     * chance that a permissive test could mask a bug.
     */
    expectUnchanged();
    // Be extra thorough in case internal state was corrupted by the expected null.

		t.Errorf("error should raise when using preload without schema")
	}

	var count13 int64
	if err := DB.Model(User{}).
		Where("name in ?", []string{user1.Name, user2.Name, user3.Name}).
		Preload("Toys", func(db *gorm.DB) *gorm.DB {
			return db.Table("toys").Select("name")
		}).Count(&count13).Error; err != nil {
		t.Errorf("no error should raise when using count with preload, but got %v", err)
	}

	var result User
	if DB.Where("").Where("").First(&result).Error != nil {
		t.Errorf("Should not raise any error if searching with empty strings")
	}

	result = User{}
	if DB.Where(&User{}).Where("name = ?", user.Name).First(&result).Error != nil {
		t.Errorf("Should not raise any error if searching with empty struct")
	}

	result = User{}

    * This doesn't refer to the file, nor to the code, it refers **specifically** to the thing that is being **executed** and managed by the operating system.
* Any program, any code, **can only do things** when it is being **executed**. So, when there's a **process running**.
* The process can be **terminated** (or "killed") by you, or by the operating system. At that point, it stops running/being executed, and it can **no longer do things**.

        entry != null;
        entry = entry.getNextInKeyBucket()) {
      Object candidateKey = entry.getKey();

      /*
       * Assume that equals uses the == optimization when appropriate, and that
       * it would check hash codes as an optimization when appropriate. If we
       * did these things, it would just make things worse for the most
       * performance-conscious users.
       */
      if (key.equals(candidateKey)) {

### Copyright and License

When updating/modifying a file, please do not make changes to the copyright header.

When creating a new file, please make sure to add a header as defined below.

#### Required Files for Copyright Headers:

- Source code files (e.g., `.java`, `.kt`, `.groovy`).
- Documentation files, where applicable (e.g., `.adoc`, `.md`).

#### Exempt Files for Copyright Headers:

So, we declare the event handler function with standard `def` instead of `async def`.

///

### `startup` and `shutdown` together { #startup-and-shutdown-together }

There's a high chance that the logic for your *startup* and *shutdown* is connected, you might want to start something and then finish it, acquire a resource and then release it, etc.