pkg database/sql, method (*DB) Conn(context.Context) (*Conn, error)
pkg database/sql, type Conn struct
pkg database/sql, type Out struct
pkg database/sql, type Out struct, Dest interface{}
pkg database/sql, type Out struct, In bool
pkg database/sql, var ErrConnDone error
pkg database/sql/driver, type NamedValueChecker interface { CheckNamedValue }

            sessionChannels.remove(sessionId);
            throw new CIFSException("Failed to create channels for session " + sessionId, e);
        }
    }

    /**
     * Selects the best channel for an operation.
     *
     * @param sessionId the session identifier
     * @return the selected channel, or null if no channels available
     */
    public ChannelInfo selectChannel(String sessionId) {

---

**FastAPI** doesn't make any compromise with any database, data model or tool.

It gives you all the flexibility to choose the ones that fit your project the best.

And you can use directly many well maintained and widely used packages like `passlib` and `PyJWT`, because **FastAPI** doesn't require any complex mechanisms to integrate external packages.

    SQLModel will know that something declared as `str` will be a SQL column of type `TEXT` (or `VARCHAR`, depending on the database).

### Create an Engine { #create-an-engine }

A SQLModel `engine` (underneath it's actually a SQLAlchemy `engine`) is what **holds the connections** to the database.

/// tip

This is a somewhat advanced technique, and in most of the cases you won't really need it, as you can raise exceptions (including `HTTPException`) from inside of the rest of your application code, for example, in the *path operation function*.

But it's there for you if you need it. 🤓

///

{* ../../docs_src/dependencies/tutorial008b_an_py39.py hl[18:22,31] *}

   * recognize certain cases where distinct {@code Equivalence} instances would in fact behave
   * identically. However, as code migrates to {@code java.util.function}, that behavior will
   * disappear. It is best not to depend on it.
   */
  @Override
  public boolean equals(@Nullable Object object) {
    return super.equals(object);
  }

  /**
   * Returns a hash code for {@code t}.
   *

        for (NetworkInterfaceInfo info : response.getInterfaces()) {
            if (info.isUsableForChannel()) {
                remoteInterfaces.add(info);
            }
        }

        // Sort by score (best interfaces first)
        remoteInterfaces.sort((a, b) -> Integer.compare(b.getScore(), a.getScore()));

        log.debug("Discovered {} remote network interfaces", remoteInterfaces.size());
    }

Mithilfe des Zertifikats entscheiden der Client und der TLS-Terminierungsproxy dann, **wie der Rest der TCP-Kommunikation verschlüsselt werden soll**. Damit ist der **TLS-Handshake** abgeschlossen.

 *       (in a way that affects its {@link Object#equals} behavior) while it is contained in a
 *       collection. Undefined behavior and bugs will result. It's generally best to avoid using
 *       mutable objects as elements at all, as many users may expect your "immutable" object to be
 *       <i>deeply</i> immutable.
 * </ul>
 *
 * <h4>Performance notes</h4>
 *
 * <ul>

  public static final String SEC_CH_DPR = "Sec-CH-DPR";

  /**
   * The HTTP <a href="https://w3c.github.io/webappsec-fetch-metadata/">{@code Sec-Fetch-Dest}</a>
   * header field name.
   *
   * @since 27.1
   */
  public static final String SEC_FETCH_DEST = "Sec-Fetch-Dest";

  /**
   * The HTTP <a href="https://w3c.github.io/webappsec-fetch-metadata/">{@code Sec-Fetch-Mode}</a>
   * header field name.
   *