oracle 0.0.5

Oracle binding
Documentation

Rust-oracle

This is an Oracle database driver for Rust based on ODPI-C.

Don't use this until the version number reaches to 0.1.0. Methods for executing SQL statements are almost ready for 0.1.0. However methods for establishing connections will be changed. Especially Connector may or may not be removed.

Methods for querying rows were changed in 0.0.4. If you had written programs using rust-oracle before 0.0.4, enable the restore-deleted feature in Cargo.toml. It restores deleted methods and disables statement-type checking in execute methods.

Change Log

0.0.5

New features:

  • Add query methods to Connection to fetch rows without using Statement.
    • Connection.query()
    • Connection.query_named()
    • Connection.query_as()
    • Connection.query_as_named()
  • Add query_row methods to Statement to fetch a first row without using ResultSet.
    • Statement.query_row()
    • Statement.query_row_named()
    • Statement.query_row_as()
    • Statement.query_row_as_named()

Incompatible changes:

  • Merge RowResultSet struct into RowValueResultSet and rename it to ResultSet.

0.0.4

New features:

  • Add query methods to Statement to fetch rows as iterator.
    • Statement.query()
    • Statement.query_named()
    • Statement.query_as()
    • Statement.query_as_named()
  • Add query_row methods to Connection to fetch a first row without using Statement.
    • Connection.query_row()
    • Connection.query_row_named()
    • Connection.query_row_as()
    • Connection.query_row_as_named()
  • Autocommit mode.

Incompatible changes:

  • Execute methods fail for select statements. Use query methods instead.
    • Connection.execute()
    • Connection.execute_named()
    • Statement.execute()
    • Statement.execute_named()
  • Renamed traits, methods and variants.
    • ColumnValues → RowValue
    • Row.values() → Row.get_as()
    • Row.columns() → Row.sql_values()
    • Error::Overflow → Error::OutOfRange
  • Removed methods.
    • Statement.column_count()
    • Statement.column_names()
    • Statement.column_info()
    • Statement.fetch()
    • SqlValue.clone()

Build-time Requirements

  • Rust 1.19 or later
  • C compiler. See Compile-time Requirements in this document.

Run-time Requirements

Usage

Put this in your Cargo.toml:

[dependencies]
oracle = "0.0.5"

When you need to fetch or bind chrono data types, enable chrono feature:

[dependencies]
oracle = { version = "0.0.5", features = ["chrono"] }

If you had written programs using rust-oracle before 0.0.4, try the restore-deleted feature. It restores deleted methods and disables statement-type checking in execute methods.

[dependencies]
oracle = { version = "0.0.5", features = ["restore-deleted"] }

Then put this in your crate root:

extern crate oracle;

Examples

Executes select statements and get rows:

// Connect to a database.
let conn = oracle::Connection::new("scott", "tiger", "//localhost/XE").unwrap();

let sql = "select ename, sal, comm from emp where deptno = :1";

// Select a table with a bind variable.
println!("---------------|---------------|---------------|");
let rows = conn.query(sql, &[&30]).unwrap();
for row_result in rows {
    let row = row_result.unwrap();
    // get a column value by position (0-based)
    let ename: String = row.get(0).unwrap();
    // get a column by name (case-insensitive)
    let sal: i32 = row.get("sal").unwrap();
    // Use `Option<...>` to get a nullable column.
    // Otherwise, `Err(oracle::Error::NullValue)` is returned
    // for null values.
    let comm: Option<i32> = row.get(2).unwrap();

    println!(" {:14}| {:>10}    | {:>10}    |",
             ename,
             sal,
             comm.map_or("".to_string(), |v| v.to_string()));
}

// Another way to fetch rows.
// The rows iterator returns Result<(String, i32, Option<i32>)>.
println!("---------------|---------------|---------------|");
let rows = conn.query_as::<(String, i32, Option<i32>)>(sql, &[&10]).unwrap();
for row_result in rows {
    let (ename, sal, comm) = row_result.unwrap();
    println!(" {:14}| {:>10}    | {:>10}    |",
             ename,
             sal,
             comm.map_or("".to_string(), |v| v.to_string()));
}

Executes select statements and get the first rows:

// Connect to a database.
let conn = oracle::Connection::new("scott", "tiger", "//localhost/XE").unwrap();

let sql = "select ename, sal, comm from emp where empno = :1";

// Print the first row.
let row = conn.query_row(sql, &[&7369]).unwrap();
let ename: String = row.get("empno").unwrap();
let sal: i32 = row.get("sal").unwrap();
let comm: Option<i32> = row.get("comm").unwrap();
println!("---------------|---------------|---------------|");
println!(" {:14}| {:>10}    | {:>10}    |",
         ename,
         sal,
         comm.map_or("".to_string(), |v| v.to_string()));
// When no rows are found, conn.query_row() returns `Err(oracle::Error::NoMoreData)`.

// Get the first row as a tupple
let row = conn.query_row_as::<(String, i32, Option<i32>)>(sql, &[&7566]).unwrap();
println!("---------------|---------------|---------------|");
println!(" {:14}| {:>10}    | {:>10}    |",
         row.0,
         row.1,
         row.2.map_or("".to_string(), |v| v.to_string()));

Executes non-select statements:

// Connect to a database.
let conn = oracle::Connection::new("scott", "tiger", "//localhost/XE").unwrap();

conn.execute("create table person (id number(38), name varchar2(40))", &[]).unwrap();

// Execute a statement with positional parameters.
conn.execute("insert into person values (:1, :2)",
             &[&1, // first parameter
               &"John" // second parameter
              ]).unwrap();

// Execute a statement with named parameters.
conn.execute_named("insert into person values (:id, :name)",
                   &[("id", &2), // 'id' parameter
                     ("name", &"Smith"), // 'name' parameter
                    ]).unwrap();

// Commit the transaction.
conn.commit().unwrap();

// Delete rows
conn.execute("delete from person", &[]).unwrap();

// Rollback the transaction.
conn.rollback().unwrap();

Prints column information:

// Connect to a database.
let conn = oracle::Connection::new("scott", "tiger", "//localhost/XE").unwrap();

let sql = "select ename, sal, comm from emp where 1 = 2";
let rows = conn.query(sql, &[]).unwrap();

// Print column names
for info in rows.column_info() {
    print!(" {:14}|", info.name());
}
println!("");

// Print column types
for info in rows.column_info() {
    print!(" {:14}|", info.oracle_type().to_string());
}
println!("");

Prepared statement:

let conn = oracle::Connection::new("scott", "tiger", "//localhost/XE").unwrap();

// Create a prepared statement
let mut stmt = conn.prepare("insert into person values (:1, :2)").unwrap();
// Insert one row
stmt.execute(&[&1, &"John"]).unwrap();
// Insert another row
stmt.execute(&[&2, &"Smith"]).unwrap();

This is more efficient than two conn.execute(). An SQL statement is executed in the DBMS as follows:

  • step 1. Parse the SQL statement and create an execution plan.
  • step 2. Execute the plan with bind parameters.

When a prepared statement is used, step 1 is called only once.

NLS_LANG parameter

NLS_LANG consists of three components: language, territory and charset. However the charset component is ignored and UTF-8(AL32UTF8) is used as charset because rust characters are UTF-8.

The territory component specifies numeric format, date format and so on. However it affects only conversion in Oracle. See the following example:

// The territory is France.
std::env::set_var("NLS_LANG", "french_france.AL32UTF8");
let conn = oracle::Connection::new("scott", "tiger", "").unwrap();

// 10.1 is converted to a string in Oracle and fetched as a string.
let result = conn.query_row_as::<String>("select to_char(10.1) from dual", &[]).unwrap();
assert_eq!(result, "10,1"); // The decimal mark depends on the territory.

// 10.1 is fetched as a number and converted to a string in rust-oracle
let result = conn.query_row_as::<String>("select 10.1 from dual", &[]).unwrap();
assert_eq!(result, "10.1"); // The decimal mark is always period(.).

Note that NLS_LANG must be set before first rust-oracle function execution if required.

TODO

  • Connection pooling
  • Read and write LOB as stream
  • REF CURSOR, BOOLEAN
  • Scrollable cursors
  • Batch DML
  • DML returning

License

Rust-oracle itself is under 2-clause BSD-style license.

ODPI-C bundled in rust-oracle is under the terms of:

  1. the Universal Permissive License v 1.0 or at your option, any later version; and/or
  2. the Apache License v 2.0.