Struct RefCursor

pub struct RefCursor { /* private fields */ }

Result set output by or returned by a PL/SQL block or a stored procedure

This struct has four query methods, which are similar to Statement’s query methods excluding params arguments. The latter methods internally execute statements with specified params and then get query results. On the other hand, the former get query results executed in a PL/SQL block or a stored procedure. So there are no params arguments in this struct.

When settings about queries are set to StatementBuilder, they are also applied to ref cursors output by a PL/SQL. It is worth to call StatementBuilder::fetch_array_size(1) in order to reduce memory usage when a ref cursor contains at most one row.

Examples

Ref cursor as an output parameter

let sql = r#"
begin
  open :cursor for select IntCol, StringCol from TestStrings order by IntCol;
end;
"#;
let mut stmt = conn.statement(sql).build()?;
stmt.execute(&[&None::<RefCursor>])?;

let mut cursor: RefCursor = stmt.bind_value(1)?;
let mut n = 1;
for row_result in cursor.query_as::<(i32, String)>()? {
    let (int_col, string_col) = row_result?;
    assert_eq!(int_col, n);
    assert_eq!(string_col, format!("String {}", n));
    n += 1;
}

Ref cursor returned by a PL/SQL block

let sql = r#"
declare
  cursor1 SYS_REFCURSOR;
begin
  open cursor1 for select IntCol, StringCol from TestStrings order by IntCol;
  dbms_sql.return_result(cursor1);
end;
"#;
let mut stmt = conn.statement(sql).build()?;
stmt.execute(&[])?;

// Get the result set.
let mut opt_cursor = stmt.implicit_result()?;
assert!(opt_cursor.is_some());
let mut cursor = opt_cursor.unwrap();
let mut n = 1;
for row_result in cursor.query_as::<(i32, String)>()? {
    let (int_col, string_col) = row_result?;
    assert_eq!(int_col, n);
    assert_eq!(string_col, format!("String {}", n));
    n += 1;
}

Implementations

impl RefCursor

pub fn query(&mut self) -> Result<ResultSet<'_, Row>>

Gets rows as an iterator of Rows.

Examples

let sql = r#"
begin
  open :cursor for select IntCol, StringCol from TestStrings order by IntCol;
end;
"#;
let mut stmt = conn.statement(sql).build()?;
stmt.execute(&[&None::<RefCursor>])?;

let mut cursor: RefCursor = stmt.bind_value(1)?;
let mut n = 1;
for row_result in cursor.query()? {
    let row = row_result?;
    let int_col: i32 = row.get(0)?;
    let string_col: String = row.get(1)?;
    assert_eq!(int_col, n);
    assert_eq!(string_col, format!("String {}", n));
    n += 1;
}

pub fn query_as<T>(&mut self) -> Result<ResultSet<'_, T>>

where T: RowValue,

Gets rows as an itertor of the specified type.

Examples

let sql = r#"
begin
  open :cursor for select IntCol, StringCol from TestStrings order by IntCol;
end;
"#;
let mut stmt = conn.statement(sql).build()?;
stmt.execute(&[&None::<RefCursor>])?;

let mut cursor: RefCursor = stmt.bind_value(1)?;
let mut n = 1;
for row_result in cursor.query_as::<(i32, String)>()? {
    let (int_col, string_col) = row_result?;
    assert_eq!(int_col, n);
    assert_eq!(string_col, format!("String {}", n));
    n += 1;
}

pub fn query_row(&mut self) -> Result<Row>

Gets one row as Row.

Examples

let sql = r#"
begin
  open :cursor for select StringCol from TestStrings where IntCol = :IntCol;
end;
"#;
let mut stmt = conn.statement(sql).fetch_array_size(1).build()?;
stmt.execute(&[&None::<RefCursor>, &1])?;

let mut cursor: RefCursor = stmt.bind_value(1)?;
let string_col: String = cursor.query_row()?.get(0)?;
assert_eq!(string_col, "String 1");

pub fn query_row_as<T>(&mut self) -> Result<T>

where T: RowValue,

Gets one row as the specified type.

Examples

let sql = r#"
begin
  open :cursor for select StringCol from TestStrings where IntCol = :IntCol;
end;
"#;
let mut stmt = conn.statement(sql).fetch_array_size(1).build()?;
stmt.execute(&[&None::<RefCursor>, &1])?;

let mut cursor: RefCursor = stmt.bind_value(1)?;
assert_eq!(cursor.query_row_as::<String>()?, "String 1");

Trait Implementations

impl FromSql for RefCursor

fn from_sql(val: &SqlValue<'_>) -> Result<Self>

impl ToSql for RefCursor

fn oratype(&self, _conn: &Connection) -> Result<OracleType>

fn to_sql(&self, _val: &mut SqlValue<'_>) -> Result<()>

impl ToSqlNull for RefCursor

fn oratype_for_null(_conn: &Connection) -> Result<OracleType>