"}.sr-only{border:0;clip:rect(0,0,0,0);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}.sr-only-focusable:active,.sr-only-focusable:focus{clip:auto;height:auto;margin:0;overflow:visible;position:static;width:auto}@font-face{font-family:"Font Awesome 5 Brands";font-style:normal;font-weight:normal;font-display:auto;src:url(./fonts/fa-brands-400.eot);src:url(./fonts/fa-brands-400.eot?#iefix) format("embedded-opentype"),url(./fonts/fa-brands-400.woff2) format("woff2"),ur...

### Create Models

Import `SQLModel` and create a database model:

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[1:11] hl[7:11] *}

The `Hero` class is very similar to a Pydantic model (in fact, underneath, it actually *is a Pydantic model*).

There are a few differences:

      BaseEncoding encoding, String cannotDecode, @Nullable String expectedMessage) {
    // We use this somewhat weird pattern with an enum for each assertion we want to make as a way
    // of dealing with the fact that one of the assertions is @GwtIncompatible but we don't want to
    // have to have duplicate @GwtIncompatible test methods just to make that assertion.

     * and the arithmetic mean is always higher than the geometric mean.
     *
     * b) this iteration converges to floor(sqrt(x)). In fact, the number of correct digits doubles
     * with each iteration, so this algorithm takes O(log(digits)) iterations.
     *
     * We start out with a double-precision approximation, which may be higher or lower than the

Many of the tutorials have blocks of code.

In most of the cases, these blocks of code are actual complete applications that can be run as is.

In fact, those blocks of code are not written inside the Markdown, they are Python files in the `./docs_src/` directory.

And those Python files are included/injected in the documentation when generating the site.

### Docs for tests

     * just to be safe.
     *
     * The real purpose of this test is to produce a TSAN failure if MapIteratorCache is unsafe for
     * reads from multiple threads -- unsafe, in fact, even in the absence of a concurrent write.
     * The specific problem we had was unsafe reads of lastEntryReturnedBySomeIterator. (To fix the
     * problem, we've since marked that field as volatile.)
     *

  }

  /**
   * This test is for a case where two Service.Listener callbacks for the same service would call
   * transitionService in the wrong order due to a race. Due to the fact that it is a race this test
   * isn't guaranteed to expose the issue, but it is at least likely to become flaky if the race
   * sneaks back in, and in this case flaky means something is definitely wrong.
   *

	go func() { a = "hello" }()
	print(a)
}
</pre>

<p>
the assignment to <code>a</code> is not followed by
any synchronization event, so it is not guaranteed to be
observed by any other goroutine.
In fact, an aggressive compiler might delete the entire <code>go</code> statement.
</p>

<p>
If the effects of a goroutine must be observed by another goroutine,
use a synchronization mechanism such as a lock or channel

   * this range. Note that discrete ranges such as {@code (1..4)} and {@code [2..3]} are <b>not</b>
   * equal to one another, despite the fact that they each contain precisely the same set of values.
   * Similarly, empty ranges are not equal unless they have exactly the same representation, so
   * {@code [3..3)}, {@code (3..3]}, {@code (4..4]} are all unequal.
   */

  /**
   * Maximum parts (labels) in a domain name. This value arises from the 255-octet limit described
   * in <a href="http://www.ietf.org/rfc/rfc2181.txt">RFC 2181</a> part 11 with the fact that the
   * encoding of each part occupies at least two bytes (dot plus label externally, length byte plus
   * label internally). Thus, if all labels have the minimum size of one byte, 127 of them will fit.
   */