bind_columns/
bind_columns.rs

1//! Binds columns to a result set and fills them with fetch. This is still super akward.
2extern crate odbc_safe;
3extern crate odbc_sys;
4use odbc_safe::*;
5use odbc_sys::SQLLEN;
6use std::str::from_utf8;
7
8// Setup error handling
9struct LastError(String);
10type MyResult<T> = Result<T, LastError>;
11
12impl<D: Diagnostics> From<D> for LastError {
13    fn from(source: D) -> Self {
14        let mut buffer = [0; 512];
15        match source.diagnostics(1, &mut buffer) {
16            ReturnOption::Success(dr) |
17            ReturnOption::Info(dr) => LastError(
18                from_utf8(&buffer[0..(dr.text_length as usize)])
19                    .unwrap()
20                    .to_owned(),
21            ),
22            ReturnOption::Error(()) => panic!("Error during fetching diagnostic record"),
23            ReturnOption::NoData(()) => LastError("No Diagnostic Record present".to_owned()),
24        }
25    }
26}
27
28trait ExtReturn<T> {
29    fn into_result(self) -> MyResult<T>;
30}
31
32impl<T, D> ExtReturn<T> for Return<T, D>
33where
34    D: Diagnostics,
35{
36    fn into_result(self) -> MyResult<T> {
37        match self {
38            Success(v) | Info(v) => Ok(v),
39            Error(d) => Err(d.into()),
40        }
41    }
42}
43
44// Actual application
45fn main() {
46
47    let env = Environment::new().unwrap();
48    let env = env.declare_version_3().unwrap();
49
50    match run(&env) {
51        Ok(()) => (),
52        Err(LastError(message)) => println!("An error occurred: {}", message),
53    }
54}
55
56fn run(env: &Environment<Odbc3>) -> MyResult<()> {
57
58    let conn = connect(env)?;
59    let result_set = execute_query(&conn)?;
60    print_fields(result_set)
61}
62
63fn connect<V>(env: &Environment<V>) -> MyResult<Connection<impl AutocommitMode>>
64where
65    V: Version,
66{
67    let conn = DataSource::with_parent(env).unwrap();
68    conn.connect("TestDataSource", "", "").into_result()
69}
70
71fn execute_query<'a, AC: AutocommitMode>(conn: &'a Connection<AC>) -> MyResult<ResultSet<'a, 'a, 'a, Unprepared>> {
72    let stmt = Statement::with_parent(conn).unwrap();
73    match stmt.exec_direct("SELECT year, title FROM Movies") {
74        ReturnOption::Success(s) |
75        ReturnOption::Info(s) => Ok(s),
76        ReturnOption::NoData(_) => Err(LastError(
77            "Statement did not return a Result Set.".to_owned(),
78        )),
79        ReturnOption::Error(e) => Err(e.into()),
80    }
81}
82
83fn print_fields(result_set: ResultSet<Unprepared>) -> MyResult<()> {
84    let mut year = 0;
85    let mut title = [0u8; 512];
86    let mut ind_year = 0;
87    let mut ind_title = 0;
88    let mut cursor_opt = fetch(
89        result_set,
90        &mut year,
91        &mut title,
92        &mut ind_year,
93        &mut ind_title,
94    )?;
95    while let Some(p) = cursor_opt {
96        println!(
97            "year: {}, title: {}",
98            year,
99            from_utf8(&title[0..(ind_title as usize)]).unwrap()
100        );
101        cursor_opt = fetch(p, &mut year, &mut title, &mut ind_year, &mut ind_title)?
102    }
103    Ok(())
104}
105
106fn fetch<'con, 'p, 'c, C>(
107    cursor: Statement<'con, 'p, 'c, C>,
108    year: &mut u32,
109    title: &mut [u8],
110    ind_year: &mut SQLLEN,
111    ind_title: &mut SQLLEN,
112) -> MyResult<Option<Statement<'con, 'p, 'c, Positioned>>>
113where
114    C: CursorState,
115{
116    use ReturnOption::*;
117    let cursor = cursor.bind_col(1, year, Some(ind_year)).into_result()?;
118    let cursor = cursor.bind_col(2, &mut title[..], Some(ind_title)).into_result()?;
119    let cursor = match cursor.fetch() {
120        Success(s) | Info(s) => Some(s.reset_columns()),
121        NoData(_) => None,
122        Error(s) => return Err(s.into()),
123    };
124    Ok(cursor)
125}
bind_columns/bind_columns.rs

bind_columns/
bind_columns.rs
