include-sqlite-sql is an extension of include-sql for using SQLite SQL in Rust. It completes include-sql by providing impl_sql
macro to generate database access methods from the included SQL. include-sqlite-sql uses Rusqlite for database access.
Include include-sqlite-sql
as a dependency:
toml
[dependencies]
include-sqlite-sql = "0.1"
Write your SQL and save it in a file. For example, let's say the following is the content of the library.sql
file that is saved in the project's src
folder:
```sql -- name: getloanedbooks? -- Returns the list of books loaned to a patron -- # Parameters -- param: userid: &str - user ID SELECT booktitle FROM library WHERE loanedto = :userid ORDER BY 1;
-- name: loanbooks! -- Updates the book records to reflect loan to a patron -- # Parameters -- param: userid: &str - user ID -- param: bookids: u32 - book IDs UPDATE library SET loanedto = :userid , loanedon = currenttimestamp WHERE bookid IN (:book_ids); ```
And then use it in Rust as:
```rust , ignore use includesqlitesql::{includesql, implsql}; use rusqlite::{Result, Connection};
include_sql!("src/library.sql");
fn main() -> Result<()> {
let args : Vec
let db = Connection::open(dbpath)?;
db.get_loaned_books(user_id, |row| {
let book_title : &str = row.get_ref("book_title")?.as_str()?;
println!("{}", book_title);
Ok(())
})?;
Ok(())
} ```
Note that the path to the SQL file must be specified relative to the project root, i.e. relative to
CARGO_MANIFEST_DIR
, even if you keep your SQL file alongside rust module that includes it. Because include-sql targets stable Rust this requirement will persist until SourceFile stabilizes.
Please see the Anatomy of the Included SQL File in include-sql documentation for the description of the format that include-sql can parse.
include-sqlite-sql generates 3 variants of database access methods using the following selectors:
* ?
- methods that process rows retrieved by SELECT
,
* !
- methods that execute all other non-SELECT
methods, and
* ->
- methods that execute RETURNING
statements and provide access to returned data.
For the SELECT
statement like:
sql
-- name: get_loaned_books?
-- param: user_id: &str
SELECT book_title FROM library WHERE loaned_to = :user_id;
The method with the following signature is generated:
rust , ignore
fn get_loaned_books<F>(&self, user_id: &str, row_callback: F) -> rusqlite::Result<()>
where F: Fn(&rusqlite::Row<'_>) -> rusqlite::Result<()>;
Where:
- user_id
is a parameter that has the same name as the SQL parameter with the declared (in the SQL) type as &str
.
- F
is a type of a callback (closure) that the method implementation will call to process each row.
For non-select statements - INSERT, UPDATE, DELETE, etc. - like the following:
sql
-- name: loan_books!
-- param: user_id: &str
-- param: book_ids: u32
UPDATE library
SET loaned_to = :user_id
, loaned_on = current_timestamp
WHERE book_id IN (:book_ids);
The method with the following signature is generated:
rust , ignore
fn loan_books(&self, user_id: &str, book_ids: &[u32]) -> rusqlite::Result<usize>;
Where:
- user_id
is a parameter that has the same name as the SQL parameter with the declared (in the SQL) type as &str
,
- book_ids
is a parameter for the matching IN-list parameter where each item in a collection has type u32
.
For DELETE, INSERT, and UPDATE statements that return data via RETURNING
clause like:
sql
-- name: add_new_book->
-- param: isbn: &str
-- param: book_title: &str
INSERT INTO library (isbn, book_title)
VALUES (:isbn, :book_title)
RETURNING book_id;
The method with the following signature is generated:
rust , ignore
fn add_new_book<F,R>(&self, isbn: &str, book_title: &str, row_callback: F) -> rusqlite::Result<R>
where F: FnOnce(&rusqlite::Row<'_>) -> rusqlite::Result<R>;
If a statement parameter type is not explicitly specified via param:
, include-sqlite-sql will use impl rusqlite::ToSql
for the corresponding method parameters. For example, if the SQL from the example above has not provided its parameter type:
sql
-- name: get_loaned_books?
-- Returns the list of books loaned to a patron
SELECT book_title
FROM library
WHERE loaned_to = :user_id
ORDER BY 1;
Then the signature of the generated method would be:
rust , ignore
/// Returns the list of books loaned to a patron
fn get_loaned_books<F>(&self, user_id: impl rusqlite::ToSql, row_callback: F) -> rusqlite::Result<()>
where F: Fn(&rusqlite::Row<'_>) -> rusqlite::Result<()>;