Merge pull request #34 from sqlcj-dev/chore/sample-search-count-page-and-left-join

docs: demonstrate everyday reads in the sample and quickstart

Author: omer-cengel

docs/quickstart.md

@@ -1,7 +1,7 @@
 # Quickstart
 
-This walkthrough builds a small Maven application that reads and writes a
-PostgreSQL table through sqlcj-generated Java. Every file is listed in full, so
+This walkthrough builds a small Maven application that reads and writes two
+PostgreSQL tables through sqlcj-generated Java. Every file is listed in full, so
 the steps can be followed from an empty directory.
 
 The finished project uses only the packaged sqlcj artifacts: the executable CLI
@@ -169,6 +169,13 @@ CREATE TABLE authors
     bio        TEXT,
     created_at TIMESTAMP
 );
+
+CREATE TABLE books
+(
+    id        BIGSERIAL PRIMARY KEY,
+    author_id BIGINT       NOT NULL REFERENCES authors (id),
+    title     VARCHAR(255) NOT NULL
+);
 ```
 
 The accepted column types and `CREATE TABLE` constructs are listed in
@@ -206,16 +213,47 @@ WHERE id = $1;
 DELETE
 FROM authors
 WHERE id = $1;
+
+-- name: SearchAuthors :many
+SELECT *
+FROM authors
+WHERE name ILIKE $1
+ORDER BY id;
+
+-- name: CountAuthors :one
+SELECT COUNT(*) AS total
+FROM authors;
+
+-- name: ListAuthorPage :many
+SELECT *
+FROM authors
+ORDER BY id
+LIMIT $1 OFFSET $2;
+
+-- name: CreateBook :exec
+INSERT INTO books (author_id, title)
+VALUES ($1, $2);
+
+-- name: ListAuthorBooks :many
+SELECT a.name, b.title
+FROM authors a
+LEFT JOIN books b ON b.author_id = a.id
+ORDER BY a.id, b.id;
 ```
 
-All six queries become methods of the one generated `AuthorRepository`:
-`createAuthor`, `getAuthor`, `findAuthor`, `listAuthors`, `updateAuthorBio`, and
-`deleteAuthor`. `CreateAuthor`, `GetAuthor`, `FindAuthor`, and `ListAuthors`
-each return one complete `authors` row, so all four share the nested record
-`AuthorRepository.AuthorsRow`, generated once from the schema's column order. A
-query with its own result shape, such as a partial projection or a `RETURNING`
-column list, generates a nested `AuthorRepository.<QueryName>Result` record
-instead.
+All eleven queries become methods of the one generated `AuthorRepository`:
+`createAuthor`, `getAuthor`, `findAuthor`, `listAuthors`, `updateAuthorBio`,
+`deleteAuthor`, `searchAuthors`, `countAuthors`, `listAuthorPage`, `createBook`,
+and `listAuthorBooks`. `CreateAuthor`, `GetAuthor`, `FindAuthor`, `ListAuthors`,
+`SearchAuthors`, and `ListAuthorPage` each return one complete `authors` row, so
+all six share the nested record `AuthorRepository.AuthorsRow`, generated once
+from the schema's column order. A query with its own result shape, such as a
+partial projection or a `RETURNING` column list, generates a nested
+`AuthorRepository.<QueryName>Result` record instead: `CountAuthors` generates
+`CountAuthorsResult` with the single non-null `Long` component `total`, and
+`ListAuthorBooks` generates `ListAuthorBooksResult` with the components `name`
+and `title`, where `title` is `null` for an author that the left-joined `books`
+table does not match.
 
 `GetAuthor` and `FindAuthor` read the same row by the same key and differ only
 in cardinality: `getAuthor` returns `AuthorsRow` and requires exactly one row,
@@ -273,6 +311,8 @@ public final class App {
             System.out.println("missing row rejected: " + e.getMessage());
         }
 
+        Long committedId;
+
         try (Connection connection = dataSource.getConnection()) {
             connection.setAutoCommit(false);
 
@@ -284,7 +324,9 @@ public final class App {
 
             connection.commit();
 
-            System.out.println("committed: " + authors.getAuthor(committed.id()).bio());
+            committedId = committed.id();
+
+            System.out.println("committed: " + authors.getAuthor(committedId).bio());
         }
 
         try (Connection connection = dataSource.getConnection()) {
@@ -301,6 +343,24 @@ public final class App {
             System.out.println("rolled back: " + authors.findAuthor(discarded.id()).isPresent());
         }
 
+        for (AuthorRepository.AuthorsRow author : authors.searchAuthors("%lovelace%")) {
+            System.out.println("searched: " + author.id() + " " + author.name());
+        }
+
+        System.out.println("count: " + authors.countAuthors().total());
+
+        for (AuthorRepository.AuthorsRow author : authors.listAuthorPage(1, 1)) {
+            System.out.println("page: " + author.id() + " " + author.name());
+        }
+
+        int bookRows = authors.createBook(committedId, "The Education of a Computer");
+
+        System.out.println("created book rows: " + bookRows);
+
+        for (AuthorRepository.ListAuthorBooksResult book : authors.listAuthorBooks()) {
+            System.out.println("book: " + book.name() + " / " + book.title());
+        }
+
         System.out.println("deleted rows: " + authors.deleteAuthor(created.id()));
     }
 
@@ -376,6 +436,12 @@ missing row: false
 missing row rejected: Query 'GetAuthor' in AuthorRepository returned no row; expected exactly one
 committed: Compiler pioneer
 rolled back: false
+searched: 1 Ada Lovelace
+count: 2
+page: 2 Grace Hopper
+created book rows: 1
+book: Ada Lovelace / null
+book: Grace Hopper / The Education of a Computer
 deleted rows: 1
 ```
 
@@ -393,10 +459,24 @@ That output is the whole MVP contract in one run:
   missing, rolled back, or deleted author.
 - `ListAuthors` is a `:many` read, and returns an empty list when no row
   matches.
-- `UpdateAuthorBio` and `DeleteAuthor` are `:exec` writes and return their
-  affected-row counts. `UpdateAuthorBio` also shows that parameter order and
-  binding order are different things: `$1` is the first method parameter even
-  though `$2` occurs first in the SQL text.
+- `SearchAuthors` filters with `name ILIKE $1`, so the pattern is a `String`
+  parameter carrying its own `%` wildcards, and PostgreSQL matches it without
+  regard to case.
+- `CountAuthors` projects an aliased `COUNT(*)` as its only result item, so
+  `countAuthors()` returns a `CountAuthorsResult` whose `total` is a non-null
+  `Long`.
+- `ListAuthorPage` pages with `LIMIT $1 OFFSET $2`, which generates
+  `listAuthorPage(Integer limit, Integer offset)`, so asking for one row after
+  the first returns the second author alone.
+- `ListAuthorBooks` selects one column from each side of a `LEFT JOIN`, so it
+  gets its own `ListAuthorBooksResult` record and reads `title` as `null` for
+  the author with no book, even though `books.title` is declared `NOT NULL`.
+- `UpdateAuthorBio`, `DeleteAuthor`, and `CreateBook` are `:exec` writes and
+  return their affected-row counts. `UpdateAuthorBio` also shows that parameter
+  order and binding order are different things: `$1` is the first method
+  parameter even though `$2` occurs first in the SQL text. `CreateBook` writes
+  the schema's other table, so the methods of one query group may span every
+  table of its schema.
 - The two `try` blocks run generated operations on a caller-owned `Connection`
   with auto-commit disabled. The runtime never closes, commits, rolls back, or
   reconfigures that connection, so the application's own `commit` makes both
@@ -416,7 +496,7 @@ If a query is invalid, `sqlcj generate` prints one diagnostic naming the source,
 the query, and the line, and exits with status `1`:
 
 ```text
-sqlcj: Invalid query 'CountAuthorBios' in /home/dev/my-app/sql/queries.sql at line 31: Unsupported SELECT expression: Function
+sqlcj: Invalid query 'CountAuthorBios' in /home/dev/my-app/sql/queries.sql at line 57: Unsupported SELECT expression: Function
 ```
 
 Every configured source is compiled before any file is written, so a diagnostic

examples/maven-postgresql/sql/queries.sql

@@ -27,3 +27,29 @@ WHERE id = $1;
 DELETE
 FROM authors
 WHERE id = $1;
+
+-- name: SearchAuthors :many
+SELECT *
+FROM authors
+WHERE name ILIKE $1
+ORDER BY id;
+
+-- name: CountAuthors :one
+SELECT COUNT(*) AS total
+FROM authors;
+
+-- name: ListAuthorPage :many
+SELECT *
+FROM authors
+ORDER BY id
+LIMIT $1 OFFSET $2;
+
+-- name: CreateBook :exec
+INSERT INTO books (author_id, title)
+VALUES ($1, $2);
+
+-- name: ListAuthorBooks :many
+SELECT a.name, b.title
+FROM authors a
+LEFT JOIN books b ON b.author_id = a.id
+ORDER BY a.id, b.id;

examples/maven-postgresql/sql/schema.sql

@@ -5,3 +5,10 @@ CREATE TABLE authors
     bio        TEXT,
     created_at TIMESTAMP
 );
+
+CREATE TABLE books
+(
+    id        BIGSERIAL PRIMARY KEY,
+    author_id BIGINT       NOT NULL REFERENCES authors (id),
+    title     VARCHAR(255) NOT NULL
+);

examples/maven-postgresql/src/main/java/com/example/app/App.java

@@ -16,16 +16,22 @@
 /**
  * Runs the documented sqlcj workflow against PostgreSQL through generated
  * code: create, read, optional read, list, update, a missing-row read, a
- * committed transaction, a rolled back transaction, and delete.
+ * committed transaction, a rolled back transaction, a case-insensitive search,
+ * a count, a page, a book insert, a left-joined projection, and delete.
  *
- * <p>All six named queries are methods of one generated
+ * <p>All eleven named queries are methods of one generated
  * {@link AuthorRepository}. The repository is constructed once per execution
  * context: once from the {@code DataSource}-backed executor, and once more per
  * transaction from a caller-owned connection.
  *
- * <p>Create, read, optional read, and list each return one complete
- * {@code authors} row, so all four share the repository's single
- * {@link AuthorRepository.AuthorsRow} record.
+ * <p>Create, read, optional read, list, search, and page each return one
+ * complete {@code authors} row, so all six share the repository's single
+ * {@link AuthorRepository.AuthorsRow} record. A query with its own result shape
+ * generates its own record: {@link AuthorRepository.CountAuthorsResult} carries
+ * the non-null {@code Long} count, and
+ * {@link AuthorRepository.ListAuthorBooksResult} carries an author name beside
+ * the title of the left-joined {@code books} row, which is {@code null} for an
+ * author without a book.
  *
  * <p>Row absence is expressed by the {@code :optional} {@code FindAuthor}
  * query, which returns an empty {@link Optional}, while the {@code :one}
@@ -35,8 +41,8 @@
  * <p>Every step is checked, so the process exits non-zero as soon as one
  * generated operation returns an unexpected result.
  *
- * <p>The verification harness applies {@code sql/schema.sql} to an empty
- * {@code authors} table before this application runs.
+ * <p>The verification harness applies {@code sql/schema.sql} to empty
+ * {@code authors} and {@code books} tables before this application runs.
  */
 public final class App {
 
@@ -124,6 +130,50 @@ public static void main(String[] args) throws SQLException {
 
         System.out.println("rolled back: empty");
 
+        List<AuthorRepository.AuthorsRow> searched = authors.searchAuthors("%lovelace%");
+
+        checkEquals(1, searched.size(), "SearchAuthors row count");
+        checkEquals(created.id(), searched.get(0).id(), "SearchAuthors id");
+        checkEquals("Ada Lovelace", searched.get(0).name(), "SearchAuthors name");
+
+        System.out.println("searched: " + searched.get(0).id() + " " + searched.get(0).name());
+
+        AuthorRepository.CountAuthorsResult count = authors.countAuthors();
+
+        check(count != null, "CountAuthors returned no row");
+        checkEquals(2L, count.total(), "CountAuthors total");
+
+        System.out.println("count: " + count.total());
+
+        List<AuthorRepository.AuthorsRow> page = authors.listAuthorPage(1, 1);
+
+        checkEquals(1, page.size(), "ListAuthorPage row count");
+        checkEquals(committedId, page.get(0).id(), "ListAuthorPage id");
+        checkEquals("Grace Hopper", page.get(0).name(), "ListAuthorPage name");
+
+        System.out.println("page: " + page.get(0).id() + " " + page.get(0).name());
+
+        String bookTitle = "The Education of a Computer";
+
+        int bookRows = authors.createBook(committedId, bookTitle);
+
+        checkEquals(1, bookRows, "CreateBook affected rows");
+
+        System.out.println("created book rows: " + bookRows);
+
+        List<AuthorRepository.ListAuthorBooksResult> books = authors.listAuthorBooks();
+
+        checkEquals(2, books.size(), "ListAuthorBooks row count");
+        checkEquals("Ada Lovelace", books.get(0).name(), "ListAuthorBooks unmatched author name");
+        checkEquals(null, books.get(0).title(), "ListAuthorBooks unmatched title");
+        checkEquals("Grace Hopper", books.get(1).name(), "ListAuthorBooks matched author name");
+        checkEquals(bookTitle, books.get(1).title(), "ListAuthorBooks matched title");
+
+        System.out.println(
+            "author books: " + books.get(0).name() + " / " + books.get(0).title()
+                + ", " + books.get(1).name() + " / " + books.get(1).title()
+        );
+
         int deletedRows = authors.deleteAuthor(created.id());
 
         checkEquals(1, deletedRows, "DeleteAuthor affected rows");

scripts/verify-release.sh

@@ -123,7 +123,8 @@ generated_count=$(find "${generated_root}" -type f -name '*.java' | wc -l)
 [ "${generated_count}" -eq 1 ] \
     || fail "expected 1 generated source but found ${generated_count}"
 
-for method in createAuthor getAuthor findAuthor listAuthors updateAuthorBio deleteAuthor; do
+for method in createAuthor getAuthor findAuthor listAuthors updateAuthorBio deleteAuthor \
+    searchAuthors countAuthors listAuthorPage createBook listAuthorBooks; do
     grep -q " ${method}(" "${generated_package}/AuthorRepository.java" \
         || fail "the generated repository is missing the ${method} method"
 done
@@ -154,7 +155,7 @@ PGPASSWORD="${db_password}" psql \
     --set=ON_ERROR_STOP=1 \
     --quiet \
     --username "${db_user}" \
-    --command 'DROP TABLE IF EXISTS authors;' \
+    --command 'DROP TABLE IF EXISTS books, authors;' \
     --file "${sample_dir}/sql/schema.sql" \
     "${jdbc_url#jdbc:}"