odbc-iter is a Rust high level database access library based on odbc crate that uses native ODBC drivers to access a variety of databases.

With this library you can:

• connect to any database supporting ODBC standard (e.g. via unixodbc library and ODBC database driver),
• run one-off, prepared or parametrized queries,
• iterate result set via standard Iterator interface,
• automatically convert rows into:
  • tuples of Rust standard types,
  • custom type implementing a trait,
  • vector of dynamically typed values,
• create thread local connections for multithreaded applications.

Things still missing:

• Full support for binary encoded NUMERICAL type (decimals) - current Decimal implementation depends on parsing string representation of the values (can be enabled with rust_decimal feature).
• Rest of this list - please open issue in GitHub issue tracker for missing functionality, bugs, etc..

Example usage

Connect and run one-off queries with row type conversion

use odbc_iter::{Odbc, ValueRow};

// Connect to database using connection string
let connection_string = std::env::var("DB_CONNECTION_STRING")
    .expect("DB_CONNECTION_STRING environment not set");
let mut connection = Odbc::connect(&connection_string)
    .expect("failed to connect to database");

// Handle statically guards access to connection and provides query functionality
let mut db = connection.handle();

// Get single row single column value
println!("{}", db.query::<String>("SELECT 'hello world'").expect("failed to run query")
    .single().expect("failed to fetch row"));

// Iterate rows with single column
for row in db.query::<String>("SELECT 'hello world' UNION SELECT 'foo bar'")
    .expect("failed to run query") {
    println!("{}", row.expect("failed to fetch row"))
}
// Prints:
// hello world
// foo bar

// Iterate rows with multiple columns
for row in db.query::<(String, i8)>(
    "SELECT 'hello world', CAST(24 AS TINYINT) UNION SELECT 'foo bar', CAST(32 AS TINYINT)")
    .expect("failed to run query") {
    let (string, number) = row.expect("failed to fetch row");
    println!("{} {}", string, number);
}
// Prints:
// hello world 24
// foo bar 32

// Iterate rows with dynamically typed values using `ValueRow` type that can represent
// any row
for row in db.query::<ValueRow>("SELECT 'hello world', 24 UNION SELECT 'foo bar', 32")
    .expect("failed to run query") {
    println!("{:?}", row.expect("failed to fetch row"))
}
// Prints:
// [Some(String("hello world")), Some(Tinyint(24))]
// [Some(String("foo bar")), Some(Tinyint(32))]

// Implementing TryFromRow on a struct allows it to be used directly.
struct ExampleStruct {
    id: i64,
    value: String,
}

impl TryFromRow<DefaultConfiguration> for ExampleStruct {
     type Error = CustomError;

     fn try_from_row<'r, 's, 'c, S>(
         row: odbc_iter::Row<'r, 's, 'c, S, DefaultConfiguration>,
     ) -> Result<Self, Self::Error> {

         let column = row.shift_column().unwrap();
         let id = i64::try_from_column(column).unwrap();

         let column = row.shift_column().unwrap();
         let value = String::try_from_column(column).unwrap();

         Ok(ExampleStruct {
             id,
             value,
         })
     }
 }

for row in db.query::<ExampleStruct>("SELECT 24, 'hello world' UNION SELECT 32, 'foo bar')
    .expect("failed to run query") {
    let data = row.expect("failed to fetch row"));
    println!("id: {}, value: {}", data.id, data.value);
}

// Prints:
// id: 24, value: hello world
// id: 32, value: foo bar