TinyBase

Movie Database

In this demo, we build an app that showcases the relational query capabilities of TinyBase v2.0, joining together information about movies, directors, and actors.

TMDB - we use The Movie Database as the source of the movie information in this app. Thank you for a great data set to demonstrate TinyBase!

This demo includes a powerful general component called ResultSortableGrid that you should feel free to use in your own apps.

An Overview Of The Data

Before looking at code, let's familiarize ourselves with the data used in this application.

Tables

The raw data is loaded into four normalized Table objects: movies (the top 250 movies on TMDB), genres (the styles of those movies), people (actors and directors), and cast (how the actors are associated with the movies).

Naturally, there are relationships between these. For example, the directorId Cell of the movies Table references a person in the people table, and the genreId Cell references the genre Table. The cast Table is a many-to-many join that contains all the movieId/castId pairs for the top three billed actors of each movie.

TableCell Ids
moviesid, name, genreId, directorId, year, rating, overview, image
genresid, name
peopleid, name, gender, born, died, popularity, biography, image
castid, movieId, castId

Because the data is normalized (and fetched as TSV over the wire), it loads quickly. But generally this data isn't suited to render directly into the application: the user doesn't want to see the movie's directorId. They want to see the director's name!

Queries

The app therefore uses a set of queries against these underlying Table objects. These act as de-normalized 'views' of the underlying normalized data and make it easy for the application to render 'virtual' rows comprised of Cell values from multiple joined Table objects in the Store.

Some of these, like the main movies query, are set up for the lifetime of the application:

QueryFrom TablesCell Ids
moviesmovies, genres, peoplemovieId, movieName, movieImage, year, rating, genreId, genreName, overview, directorId, directorName, directorImage, castId1, castName1, castImage1, castId2, castName2, castImage2, castId3, castName3, castImage3
yearsmoviesyear, movieCount
genresmoviesgenreId, genreName, movieCount
directorsmovies, peopledirectorId, directorName, directorImage, gender, popularity, movieCount
castcast, peoplecastId, castName, castImage, gender, popularity, movieCount

Others, like the moviesForYear query, are set up when a specific page is being viewed (in that case, the detail page for a particular year):

QueryFrom TablesCell Ids
moviesForYearmovies, genresmovieId, movieName, movieImage, year, rating, genreId, genreName
moviesForGenremovies, genresmovieId, movieName, movieImage, year, rating, genreId, genreName
moviesForDirectormovies, genresmovieId, movieName, movieImage, year, rating, genreId, genreName
moviesForCastcast, movies, genresmovieId, movieName, movieImage, year, rating, genreId, genreName

You might notice that many of these queries share the same Cell Ids. You'll discover that TinyBase lets you compose queries programmatically, so we'll be able to build these queries without much repetition: the common queryMovieBasics function is used to select the same Cell Ids into most of these query views.

Refer back to this section when we start loading the data, querying the data, and rendering them into the user interface. Otherwise, that's enough preamble... let's get to some code!

Boilerplate

As per usual, we first pull in React, ReactDOM, and TinyBase:

<script src="/umd/react.production.min.js"></script>
<script src="/umd/react-dom.production.min.js"></script>
<script src="/umd/tinybase.js"></script>
<script src="/umd/ui-react.js"></script>

We need the following parts of the TinyBase API, the ui-react module, and React itself:

const {createQueries, createStore} = TinyBase;
const {
  CellView,
  Provider,
  ResultCellView,
  ResultSortedTableView,
  useCell,
  useCreateQueries,
  useCreateStore,
  useQueries,
  useResultCell,
  useResultRowIds,
  useRow,
  useSetRowCallback,
} = TinyBaseUiReact;
const {createElement, useCallback, useMemo, useState} = React;
const {render} = ReactDOM;

Initializing The Application

In the main part of the application, we want to initialize a default Store (called store) and a named Store called sessionStore. The latter serves the sole purpose of remembering the 'route' in the application, which describes which part of the user interface the user is looking at.

We also initialize a Queries object, and use the createAndInitQueries function (which we'll describe later) to set up the queries for the application.

The two Store objects and the Queries object are memoized by the useCreateStore method and useCreateQueries method so they are only created the first time the app is rendered.

const App = () => {
  const store = useCreateStore(createStore);

  const sessionStore = useCreateStore(() =>
    createStore().setCell('ui', 'route', 'currentSection', 'movies'),
  );

  const queries = useCreateQueries(store, createAndInitQueries, []);
  // ...

This application depends on loading data into the main Store the first time it is rendered. We do this by having an isLoading flag in the application's state, and setting it to false only once the asynchronous loading sequence in the (soon-to-be described) loadStore function has completed. Until then, a loading spinner is shown.

  // ...
  const [isLoading, setIsLoading] = useState(true);
  useMemo(async () => {
    await loadStore(store);
    setIsLoading(false);
  }, []);

  return (
    <Provider store={store} storesById={{sessionStore}} queries={queries}>
      <Header />
      {isLoading ? <Loading /> : <Body />}
    </Provider>
  );
}

With simple boilerplate code to load the component, off we go:

addEventListener('load', () => {
  render(<App />, document.body);
});

Basic Components

Before we get to the really interesting parts, let's dispense with the basic building blocks for the application's user interface.

Loading Spinner

First the loading spinner, a plain element with some CSS.

const Loading = () => <div id="loading" />;

This is styled as a 270° arc with a spinning animation:

#loading {
  animation: spin 1s infinite linear;
  height: 2rem;
  margin: 40vh auto;
  width: 2rem;
  &::before {
    content: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" height="2rem" viewBox="0 0 100 100"><path d="M50 10A40 40 0 1 1 10 50" stroke="black" fill="none" stroke-width="4" /></svg>');
  }
}

@keyframes spin {
  from {
    transform: rotate(0);
  }
  to {
    transform: rotate(360deg);
  }
}

Application Sections

Next the structure of the application. It has four sections: 'Movies', 'Years', 'Genres', and 'People'. We define their outer components and create a keyed collection of them. Each either shows an overview (for example, all movies) or the detail of one particular record (for example, a single movie):

const MoviesSection = ({detailId}) =>
  detailId == null ? <MoviesOverview /> : <MovieDetail movieId={detailId} />;

const YearsSection = ({detailId}) =>
  detailId == null ? <YearsOverview /> : <YearDetail year={detailId} />;

const GenresSection = ({detailId}) =>
  detailId == null ? <GenresOverview /> : <GenreDetail genreId={detailId} />;

const PeopleSection = ({detailId}) =>
  detailId == null ? <PeopleOverview /> : <PersonDetail personId={detailId} />;

const SECTIONS = {
  movies: ['Movies', MoviesSection],
  years: ['Years', YearsSection],
  genres: ['Genres', GenresSection],
  people: ['People', PeopleSection],
};

The sessionStore contains a single record in the ui Table that is called route. This is the section name and optionally a detail ID (such as the movie's ID). The useRoute hook gets this pair, and the useSetRouteCallback hook will be used to set it in response to the user clicking links in the app.

const useRoute = () => useRow('ui', 'route', 'sessionStore');
const useSetRouteCallback = (currentSection, currentDetailId) =>
  useSetRowCallback(
    'ui',
    'route',
    () => ({currentSection, currentDetailId}),
    [currentSection, currentDetailId],
    'sessionStore',
  );

Note that we're not doing anything fancy here like updating the browser's URL address or history state as the user navigates around, but we would add that in this method if we did.

(Another easy, but interesting, exercise for the reader would be to use the Checkpoints API on the sessionsStore to create an in-app history stack for the pages viewed!)

Application Header

The header component simply renders all the links for the SECTIONS object and highlights the one that matches the current route.

const Header = () => {
  const {currentSection} = useRoute();
  return (
    <nav>
      {Object.entries(SECTIONS).map(([section, [title]]) => (
        <a
          className={currentSection == section ? 'current' : ''}
          onClick={useSetRouteCallback(section, null)}
        >
          {title}
        </a>
      ))}
    </nav>
  );
};

The header also has very simple styling:

nav {
  background: #eee;
  display: flex;
  a {
    flex: 1;
    padding: 0.25rem;
    text-align: center;
    &.current {
      background: #ddd;
      font-weight: 600;
    }
  }
}

Application Body

Finally, we use the current route to load the appropriate section and render it into the main part of the application:

const Body = () => {
  const {currentSection, currentDetailId} = useRoute();
  const [, Section] = SECTIONS[currentSection];
  return (
    <main>
      <Section detailId={currentDetailId} />
    </main>
  );
};

Again, this component has minimal styling:

main {
  padding: 0.5rem;
}

Loading The Data

We now move onto the more interesting data manipulation and rendering logic in the application.

The movie data for the application is sourced from TMDB and has been converted into a tab-separated variable format. TSV files are smaller and faster than JSON to load over the wire, but nonetheless, we load them asynchronously.

The logic here should be reasonably self-evident. We extract the column names from the top of the TSV, check each row has a matching cardinality, use the first column as the Row Id, coerce numeric Cell values, and load everything into a standard Table.

const NUMERIC = /^[\d\.]+$/;

const loadTable = async (store, tableId) => {
  const rows = (
    await (await fetch(`https://tinybase.org/assets/${tableId}.tsv`)).text()
  ).split('\n');
  const cellIds = rows.shift().split('\t');
  rows.forEach((row) => {
    const cells = row.split('\t');
    if (cells.length == cellIds.length) {
      const rowId = cells.shift();
      cells.forEach((cell, c) => {
        if (cell != '') {
          if (NUMERIC.test(cell)) {
            cell = parseFloat(cell);
          }
          store.setCell(tableId, rowId, cellIds[c + 1], cell);
        }
      });
    }
  });
};

There are four raw tables used in this application, as described in our opening section. We wait for all four to load (again, asynchronously) wrapped in a single Store transaction.

const loadStore = async (store) => {
  store.startTransaction();
  await Promise.all(
    ['movies', 'genres', 'people', 'cast'].map((tableId) =>
      loadTable(store, tableId),
    ),
  );
  store.finishTransaction();
};

loadStore was the function referenced in the main App component, so once this completes, the data is loaded and we're ready to go.

Querying The Data

As described at the start of this article, there are a number of queries that are set up at the beginning of the app and which are used throughout its lifetime. These include the list of all movies with de-normalized genre, director, and cast names (a query called movies); and queries that group counts of movies by genre, year, and so on.

Since many queries throughout the app re-use the same set of fields - such as movie name, image, year, and genre - we can first create a re-usable function that specifies those Cell Ids. This can be used whenever the movies Table is the root of the query. When provided a select and join function, it selects those common columns:

const queryMovieBasics = ({select, join}) => {
  select((_, movieId) => movieId).as('movieId');
  select('name').as('movieName');
  select('image').as('movieImage');
  select('year');
  select('rating');
  select('genreId');
  select('genres', 'name').as('genreName');
  join('genres', 'genreId');
};

Notice that we use a convention in this app of suffixing [Id](/api/common/type-aliases/identity/id), Name and Image to resulting Cell Ids.

In the App component we described at the start of the article, we call a function called createAndInitQueries to initialize the queries. Here's its implementation:

const createAndInitQueries = (store) => {
  const queries = createQueries(store);
  // ...

First we define the movies query that populates the main overview of the movies section of the app, and provides the detail about the movie's overview, directors and cast.

The join to the people Table for the director name and image should be self-explanatory. What is slightly more interesting is the way we join to get the cast names and images. Each movie has up to three cast members captured in the cast many-to-many join Table - and so we join through that table three times according to their billing.

// ...
queries.setQueryDefinition('movies', 'movies', ({select, join}) => {
  queryMovieBasics({select, join});
  select('overview');
  select('directorId');
  select('directors', 'name').as('directorName');
  select('directors', 'image').as('directorImage');
  join('people', 'directorId').as('directors');
  [1, 2, 3].forEach((billing) => {
    const castJoin = `cast${billing}`;
    join('cast', (_, movieId) => `${movieId}/${billing}`).as(castJoin);
    select(castJoin, 'castId').as(`castId${billing}`);
    const actorJoin = `actors${billing}`;
    join('people', castJoin, 'castId').as(actorJoin);
    select(actorJoin, 'name').as(`castName${billing}`);
    select(actorJoin, 'image').as(`castImage${billing}`);
  });
});
// ...

For the SQL-inclined amongst you, we've created something more or less equivalent to the following query:

-- movies query
SELECT
  movies._rowId AS movieId,
  movies.name AS movieName,
  movies.image AS movieImage,
  movies.year AS year,
  movies.rating AS rating,
  movies.genreId AS genreId,
  genres.name AS genreName,
  movies.overview AS overview,
  movies.directorId AS directorId,
  directors.name AS directorName,
  directors.image AS directorImage,
  cast1.castId AS castId1,
  actors1.name AS castName1,
  actors1.image AS castImage1,
  cast2.castId AS castId2,
  actors2.name AS castName2,
  actors2.image AS castImage2,
  cast3.castId AS castId3,
  actors3.name AS castName3,
  actors3.image AS castImage3
FROM
  movies
    LEFT JOIN genres
      ON genres._rowId = movies.genreId
    LEFT JOIN people AS directors
      ON directors._rowId = movies.directorId
    LEFT JOIN cast AS cast1
      ON cast1._rowId = CONCAT(movies.movieId, '/1')
      LEFT JOIN people AS actors1
        ON actors1._rowId = cast1.castId
    LEFT JOIN cast AS cast2
      ON cast2._rowId = CONCAT(movies.movieId, '/2')
      LEFT JOIN people AS actors2
        ON actors2._rowId = cast2.castId
    LEFT JOIN cast AS cast3
      ON cast3._rowId = CONCAT(movies.movieId, '/3')
      LEFT JOIN people AS actors3
        ON actors3._rowId = cast3.castId

(Except the results in our case are reactive - not something you usually get to benefit from with a SQL-based database!)

We also create query definitions for the other persistent queries. These use the group function to count the number of movies per year, genre, and so on, used in the overview components of each of the main sections of the app.

  // ...
  queries.setQueryDefinition('years', 'movies', ({select, group}) => {
    select('year');
    select((_, rowId) => rowId).as('movieId');
    group('movieId', 'count').as('movieCount');
  });

  queries.setQueryDefinition('genres', 'movies', ({select, join, group}) => {
    select('genreId');
    select((_, rowId) => rowId).as('movieId');
    join('genres', 'genreId');
    select('genres', 'name').as('genreName');
    group('movieId', 'count').as('movieCount');
  });

  queries.setQueryDefinition('directors', 'movies', ({select, join, group}) => {
    select('directorId');
    select((_, rowId) => rowId).as('movieId');
    select('people', 'name').as('directorName');
    select('people', 'image').as('directorImage');
    select('people', 'gender');
    select('people', 'popularity');
    join('people', 'directorId');
    group('movieId', 'count').as('movieCount');
  });

  queries.setQueryDefinition('cast', 'cast', ({select, join, group}) => {
    select('castId');
    select('movieId');
    select('people', 'name').as('castName');
    select('people', 'image').as('castImage');
    select('people', 'gender');
    select('people', 'popularity');
    join('people', 'castId');
    group('movieId', 'count').as('movieCount');
  });

  return queries;
}

That's it for the main persistent queries that power most of the major views of the app. We'll refer to these by their query Id when we actually bind them to components.

The ResultSortableGrid Component

Most of the movies app is built from tabular data views, and it's nice to have a re-usable <table> rendering, complete with sorting, pagination, and formatting.

Here we introduce a common component that takes a query Id, a configuration array for the columns to render, and options for sorting and pagination. It's fully self-contained in terms of managing its own state, and wraps the underlying ResultSortedTableView provided by the TinyBase ui-react module.

The columns prop is an array of [cellId, label, component?] entries, that describe the Cell of the query to get the value from, the label to put in the top header, and optionally, a custom way to render the values. We'll use this to render movie posters next to their links, for example.

Note that we have defaultDescending default to true, since in this movies app, nearly every useful initial sorting (rating, popularity, year) is downward.

Otherwise, there is nothing movie-specific about this component! So you may find it useful to take this verbatim for yourself, whenever you need to render tabular query data.

const ResultSortableGrid = ({
  queryId,
  columns,
  defaultSortCellId,
  defaultDescending = true,
  limit = 20,
  noun = 'record',
}) => {
  const columnsKey = JSON.stringify(columns);

  const [sortCellId, setSortCellId] = useState(defaultSortCellId);
  const [descending, setDescending] = useState(defaultDescending);
  const [offset, setOffset] = useState(0);
  const count = useResultRowIds(queryId).length;

  if (offset > count) {
    setOffset(0);
  }

  const Pagination = useCallback(
    () => (
      <>
        {count} {noun}
        {count != 1 ? 's' : ''}
        {count > limit && (
          <>
            {offset > 0 ? (
              <button
                className="prev"
                onClick={() => setOffset(offset - limit)}
              />
            ) : (
              <button className="prev disabled" />
            )}
            {offset + limit < count ? (
              <button
                className="next"
                onClick={() => setOffset(offset + limit)}
              />
            ) : (
              <button className="next disabled" />
            )}
            {offset + 1} to {Math.min(count, offset + limit)}
          </>
        )}
      </>
    ),
    [count, offset, limit],
  );

  const HeadingComponent = useCallback(
    () => (
      <tr>
        {columns.map(([cellId, label], c) =>
          cellId == sortCellId ? (
            <th
              onClick={() => setDescending(!descending)}
              className={`col${c}`}
            >
              {descending ? '\u2193' : '\u2191'} {label}
            </th>
          ) : (
            <th onClick={() => setSortCellId(cellId)} className={`col${c}`}>
              {label}
            </th>
          ),
        )}
      </tr>
    ),
    [sortCellId, descending, columnsKey],
  );

  const RowComponent = useCallback(
    (props) => (
      <tr>
        {columns.map(([cellId, , CellComponent]) => (
          <td>
            {CellComponent == null ? (
              <ResultCellView {...props} cellId={cellId} />
            ) : (
              <CellComponent {...props} />
            )}
          </td>
        ))}
      </tr>
    ),
    [columnsKey],
  );

  return (
    <>
      <Pagination />
      <table>
        <HeadingComponent />
        <ResultSortedTableView
          queryId={queryId}
          cellId={sortCellId}
          descending={descending}
          offset={offset}
          limit={limit}
          resultRowComponent={RowComponent}
        />
      </table>
    </>
  );
};

This component also benefits from some light styling for the pagination buttons and the table itself:

button {
  border: 0;
  cursor: pointer;
  height: 1rem;
  padding: 0;
  vertical-align: text-top;
  width: 1rem;
  &.prev {
    margin-left: 0.5rem;
    &::before {
      content: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" height="1rem" viewBox="0 0 100 100" fill="black"><path d="M65 20v60l-30-30z" /></svg>');
    }
  }
  &.next {
    margin-right: 0.5rem;
    &::before {
      content: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" height="1rem" viewBox="0 0 100 100" fill="black"><path d="M35 20v60l30-30z" /></svg>');
    }
  }
  &.disabled {
    cursor: default;
    opacity: 0.3;
  }
}

table {
  border-collapse: collapse;
  font-size: inherit;
  line-height: inherit;
  margin-top: 0.5rem;
  table-layout: fixed;
  width: 100%;
  th,
  td {
    overflow: hidden;
    padding: 0.25rem 0.5rem 0.25rem 0;
    white-space: nowrap;
  }
  th {
    border: solid #ddd;
    border-width: 1px 0;
    cursor: pointer;
    text-align: left;
    &.col0 {
      width: 40%;
    }
    &.col1,
    &.col2,
    &.col3 {
      width: 20%;
    }
  }
  td {
    border-bottom: 1px solid #eee;
  }
}

Overview Components

We now use that component to create the major views of the application.

First, the overview of all the rated movies in the database (which displays on the 'Movies' tab when the app first loads), comprising a ResultSortableGrid that renders the movies query with four columns, sorted by rating.

const MoviesOverview = () => (
  <Page title="Rated movies">
    <ResultSortableGrid
      queryId="movies"
      columns={[
        ['movieName', 'Movie', MovieLink],
        ['year', 'Year', YearLink],
        ['rating', 'Rating'],
        ['genreName', 'Genre', GenreLink],
      ]}
      defaultSortCellId="rating"
      noun="movie"
    />
  </Page>
);

Note how three of the columns are given a custom component to render the value not as raw text but as a link. We'll describe those simple components later.

The 'Years' tab renders the years query with two columns: the year and the number of movies in that year:

const YearsOverview = () => (
  <Page title="Years">
    <ResultSortableGrid
      queryId="years"
      columns={[
        ['year', 'Year', YearLink],
        ['movieCount', 'Rated movies'],
      ]}
      defaultSortCellId="year"
      noun="year"
    />
  </Page>
);

Similarly, the 'Genres' tab renders the genres query with two columns: the genre and the number of movies in that genre:

const GenresOverview = () => (
  <Page title="Genres">
    <ResultSortableGrid
      queryId="genres"
      columns={[
        ['genreName', 'Genre', GenreLink],
        ['movieCount', 'Rated movies'],
      ]}
      defaultSortCellId="movieCount"
      noun="genre"
    />
  </Page>
);

Finally, the 'People' tab renders two tables: the directors query and the cast query with four columns each, both sorted by popularity:

const PeopleOverview = () => (
  <Page title="People">
    <h2>Directors</h2>
    <ResultSortableGrid
      queryId="directors"
      columns={[
        ['directorName', 'Director', DirectorLink],
        ['gender', 'Gender', GenderFromQuery],
        ['popularity', 'Popularity'],
        ['movieCount', 'Rated movies'],
      ]}
      defaultSortCellId="popularity"
      noun="director"
    />
    <h2>Cast</h2>
    <ResultSortableGrid
      queryId="cast"
      columns={[
        ['castName', 'Cast', CastLink],
        ['gender', 'Gender', GenderFromQuery],
        ['popularity', 'Popularity'],
        ['movieCount', 'Rated movies'],
      ]}
      defaultSortCellId="popularity"
      noun="actor"
    />
  </Page>
);

Click through each of the section headings in the app so you can see how each of these is working.

Detail Components

We also have a detail view for each section, which drills into a specific movie, year, genre, or person. Firstly, for a single movie, we isolate a row in the de-normalized movies query and render its Cell values in a page format:

const MovieDetail = ({movieId}) => {
  const props = {queryId: 'movies', rowId: movieId};
  return (
    <Page title={useResultCell('movies', movieId, 'movieName')}>
      <ImageFromQuery {...props} cellId="movieImage" isLarge={true} />
      <ul>
        <li>
          Year: <YearLink {...props} />
        </li>
        <li>
          Genre: <GenreLink {...props} />
        </li>
        <li>
          Rating: <ResultCellView {...props} cellId="rating" />
        </li>
      </ul>
      <p>
        <ResultCellView {...props} cellId="overview" />
      </p>
      <h2>Credits</h2>
      <ul>
        <li>
          <DirectorLink {...props} />, director
        </li>
        <li>
          <CastLink {...props} billing={1} />
        </li>
        <li>
          <CastLink {...props} billing={2} />
        </li>
        <li>
          <CastLink {...props} billing={3} />
        </li>
      </ul>
    </Page>
  );
};

Again, note how we are often using custom components that take the Cell values from this result Row to make links to other parts of the app. We'll describe those shortly.

Moving on, the detail for a specific year is just a sorted table of the movies from that year.

But here is a case where we need to run the query within the component (rather than globally across the app). The moviesForYear query is constructed whenever the year prop changes, and uses the where function to show the basic movie data for just those movies matching that year. We get to benefit from the queryMovieBasics function again since we just need movie Id, name, rating and genre.

const YearDetail = ({year}) => {
  const queries = useQueries();
  useMemo(
    () =>
      queries.setQueryDefinition(
        'moviesForYear',
        'movies',
        ({select, join, where}) => {
          queryMovieBasics({select, join});
          where('year', year);
        },
      ),
    [year],
  );
  return (
    <Page title={`Movies from ${year}`}>
      <ResultSortableGrid
        queryId="moviesForYear"
        columns={[
          ['movieName', 'Movie', MovieLink],
          ['rating', 'Rating'],
          ['genre', 'Genre', GenreLink],
        ]}
        defaultSortCellId="rating"
        noun="movie"
      />
    </Page>
  );
};

The genre detail page is very similar, with a where clause to match the genre's Id:

const GenreDetail = ({genreId}) => {
  const queries = useQueries();
  useMemo(
    () =>
      queries.setQueryDefinition(
        'moviesForGenre',
        'movies',
        ({select, join, where}) => {
          queryMovieBasics({select, join});
          where('genreId', genreId);
        },
      ),
    [genreId],
  );
  return (
    <Page title={`${useCell('genres', genreId, 'name')} movies`}>
      <ResultSortableGrid
        queryId="moviesForGenre"
        columns={[
          ['movieName', 'Movie', MovieLink],
          ['year', 'Year', YearLink],
          ['rating', 'Rating'],
        ]}
        defaultSortCellId="rating"
        noun="movie"
      />
    </Page>
  );
};

Finally, we build the detail page for a person. We create two queries on the fly here, one for those movies for which the person is the director, and one for those in which they are cast.

The latter is slightly more complex since it needs to use the many-to-many cast Table as its root, from where it joins to the movies Table and genres Table in turn. Nevertheless, the result Cell Ids are named to be consistent with the other queries, so that we can use the same custom components to render each part of the HTML table.

This component is also slightly more complex that the others because it is also rendering some parts of its content directly from the people Table (rather than via a query) - hence the use of the basic useCell hook and CellView component, for example.

const PersonDetail = ({personId}) => {
  const queries = useQueries();
  useMemo(
    () =>
      queries
        .setQueryDefinition(
          'moviesForDirector',
          'movies',
          ({select, join, where}) => {
            queryMovieBasics({select, join});
            where('directorId', personId);
          },
        )
        .setQueryDefinition(
          'moviesForCast',
          'cast',
          ({select, join, where}) => {
            select('movieId');
            select('movies', 'name').as('movieName');
            select('movies', 'image').as('movieImage');
            select('movies', 'year');
            select('movies', 'rating');
            select('movies', 'genreId');
            select('genres', 'name').as('genreName');
            join('movies', 'movieId');
            join('genres', 'movies', 'genreId');
            where('castId', personId);
          },
        ),
    [personId],
  );

  const props = {tableId: 'people', rowId: personId};
  return (
    <Page title={useCell('people', personId, 'name')}>
      <ImageFromTable {...props} cellId="image" isLarge={true} />
      <ul>
        <li>
          Gender: <GenderFromTable {...props} />
        </li>
        <li>
          Born: <CellView {...props} cellId="born" />
          {useCell('people', personId, 'died') && (
            <>
              ; died: <CellView {...props} cellId="died" />
            </>
          )}
        </li>
        <li>
          Popularity: <CellView {...props} cellId="popularity" />
        </li>
      </ul>
      <p>
        <CellView {...props} cellId="biography" />
      </p>

      {useResultRowIds('moviesForDirector').length == 0 ? null : (
        <>
          <h2>As director:</h2>
          <ResultSortableGrid
            queryId="moviesForDirector"
            columns={[
              ['movieName', 'Movie', MovieLink],
              ['year', 'Year', YearLink],
              ['rating', 'Rating'],
            ]}
            defaultSortCellId="rating"
            noun="rated movie"
          />
        </>
      )}

      {useResultRowIds('moviesForCast').length == 0 ? null : (
        <>
          <h2>As cast:</h2>
          <ResultSortableGrid
            queryId="moviesForCast"
            columns={[
              ['movieName', 'Movie', MovieLink],
              ['year', 'Year', YearLink],
              ['rating', 'Rating'],
            ]}
            defaultSortCellId="rating"
            noun="rated movie"
          />
        </>
      )}
    </Page>
  );
};

Linking Between Views

When you click on a movie name (wherever you see it), we'll want to take you to the movie detail. Clicking a year should take you to the list of movies for the year, a genre to the list of movies in a genre - and so on.

Here we create a collection of tiny custom components which, when passed a queryId and rowId can render a decorated link which, when clicked, update the application's route. We've been using these in the ResultSortableGrid instances above.

For example, the MovieLink component creates a link that sets the route to be the movies section, with the value of the movieId Cell from the result Row being rendered. The ImageFromQuery component we'll discuss later.

This component obviously assumes that the movieId, movieImage, and movieName Cell Ids are present in the query, so we only use this for queries that meaningfully populate those.

const MovieLink = ({queryId, rowId}) => {
  const movieId = useResultCell(queryId, rowId, 'movieId');
  return (
    <a onClick={useSetRouteCallback('movies', movieId)}>
      <ImageFromQuery queryId={queryId} rowId={rowId} cellId="movieImage" />
      <ResultCellView queryId={queryId} rowId={rowId} cellId="movieName" />
    </a>
  );
};

We do the same for queries that contain a year Cell Id, for those that contain genreId and genreName Cell Ids, and for those that contain directorId and directorName Cell Ids:

const YearLink = ({queryId, rowId}) => {
  const year = useResultCell(queryId, rowId, 'year');
  return (
    <a onClick={useSetRouteCallback('years', year)}>
      <ResultCellView queryId={queryId} rowId={rowId} cellId="year" />
    </a>
  );
};

const GenreLink = ({queryId, rowId}) => {
  const genreId = useResultCell(queryId, rowId, 'genreId');
  return (
    <a onClick={useSetRouteCallback('genres', genreId)}>
      <ResultCellView queryId={queryId} rowId={rowId} cellId="genreName" />
    </a>
  );
};

const DirectorLink = ({queryId, rowId}) => {
  const personId = useResultCell(queryId, rowId, 'directorId');
  return (
    <a onClick={useSetRouteCallback('people', personId)}>
      <ImageFromQuery queryId={queryId} rowId={rowId} cellId="directorImage" />
      <ResultCellView queryId={queryId} rowId={rowId} cellId="directorName" />
    </a>
  );
};

We do the same for actors, but for the billed cast members we need to check tor existence, in case a movie does not have three actors:

const CastLink = ({queryId, rowId, billing = ''}) => {
  const personId = useResultCell(queryId, rowId, `castId${billing}`);
  return personId == null ? null : (
    <a onClick={useSetRouteCallback('people', personId)}>
      <ImageFromQuery
        queryId={queryId}
        rowId={rowId}
        cellId={`castImage${billing}`}
      />
      <ResultCellView
        queryId={queryId}
        rowId={rowId}
        cellId={`castName${billing}`}
      />
    </a>
  );
};

Final Helper Components

We conclude with a few simple components that we've been using across the application.

These take the numeric TMDB gender Id (from the Row of a Table or the result Row of query) and render it as a string:

const GenderFromQuery = ({queryId, rowId}) =>
  genderString(useResultCell(queryId, rowId, 'gender'));

const GenderFromTable = ({tableId, rowId}) =>
  genderString(useCell(tableId, rowId, 'gender'));

const genderString = (genderId) => {
  switch (genderId) {
    case 1:
      return 'Female';
    case 2:
      return 'Male';
    case 3:
      return 'Non-binary';
    default:
      return 'Unknown';
  }
};

These take a TMDB image path (again from the Row of a Table or the result Row of query) and render it in large or small format:

const ImageFromQuery = ({queryId, rowId, cellId, isLarge}) => (
  <Image imageFile={useResultCell(queryId, rowId, cellId)} isLarge={isLarge} />
);

const ImageFromTable = ({tableId, rowId, cellId, isLarge}) => (
  <Image imageFile={useCell(tableId, rowId, cellId)} isLarge={isLarge} />
);

const Image = ({imageFile, isLarge}) => (
  <img
    src={`https://image.tmdb.org/t/p/w${isLarge ? 92 : 45}${imageFile}`}
    className={isLarge ? 'large' : ''}
  />
);

These images have some light styling:

img {
  width: 1rem;
  height: 1.5rem;
  object-fit: cover;
  vertical-align: top;
  margin: 0 0.25rem 0 0;
  &.large {
    width: 4rem;
    height: 6rem;
    margin: 0 0.5rem 1rem 0;
    object-fit: contain;
    float: left;
    + ul + * {
      clear: both;
    }
  }
}

And finally, this trivial component just wraps the main view of the application to apply a consistent title to the top of each page:

const Page = ({title, children}) => (
  <>
    <h1>{title}</h1>
    {children}
  </>
);

That's it for the JavaScript!

Default Styling

Just for completeness, here is the default CSS styling and typography that the app uses:

@font-face {
  font-family: Lato;
  src: url(https://tinybase.org/fonts/lato-light.woff2) format('woff2');
  font-weight: 400;
}

@font-face {
  font-family: Lato;
  src: url(https://tinybase.org/fonts/lato-regular.woff2) format('woff2');
  font-weight: 600;
}

* {
  box-sizing: border-box;
}

body {
  user-select: none;
  font-family: Lato, sans-serif;
  font-size: 0.8rem;
  line-height: 1.5rem;
  margin: 0;
  color: #333;
}

h1 {
  margin: 0 0 1rem;
}

h2 {
  margin: 1.5rem 0 0.5rem;
}

ul {
  padding-left: 0;
}

li {
  display: block;
  padding-bottom: 0.25rem;
}

a {
  white-space: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
  cursor: pointer;
  max-width: 100%;
  display: inline-block;
  vertical-align: top;
  color: #000;
  &:hover {
    text-decoration: underline;
  }
}

p {
  line-height: 1.2rem;
}

Conclusion

And that's it! There is quite a lot going on here, but this is arguably a complete and legitimate application that pulls in a decent amount of normalized relational data and renders it in a useful and navigable fashion.

One thing that might be easy to forget (because the movie data does not change) is that every single view rendered in this application is reactive! Were any aspect of the data dynamic, it would be automatically updated in the user interface. It's left as an exercise to the reader to explore how this might work, perhaps with movie favorite lists, or pulling dynamic data directly from TMDB.

In the meantime, as they say in the movies, that's a wrap!