Rust-oracle

master	0.2.x

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

Applications using Rust-oracle 0.1.x should use 0.2.x. The incompatibility between 0.1.x and 0.2.x is trivial so they will work well without modification. The author continues updating 0.2.x to fix bugs as long as it doesn't introduce incompatibilities.

New features are added in Rust-oracle 0.3.x or later. There are enormous incompatibilities between 0.2.x and 0.3.x. They were introduced to follow Rust way. Some parameters were removed and builder data types were added instead. Some types were moved to a submodule sql_type.

Rust-oracle 0.4.x will include breaking changes about query methods. The query methods with as may be renamed to and merged into methods without as. The params argument of Connection.prepare will be replaced with some kind of the builder pattern.

Change Log

See ChangeLog.md.

Build-time Requirements

• Rust 1.31.0 or later for rust-oracle 0.3.0 and later.
• Rust 1.19.0 or later for rust-oarcle 0.1.x and 0.2.x.
• C compiler. See Compile-time Requirements in this document.

Run-time Requirements

• Oracle client 11.2 or later. See ODPI-C installation document.

Usage

Put this in your Cargo.toml:

[dependencies]
oracle = "0.3.0"

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

[dependencies]
oracle = { version = "0.3.0", features = ["chrono"] }

Then put this in your crate root:

extern crate oracle;

Examples

Executes select statements and get rows:

use oracle::{Connection, Error};

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

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])?;
for row_result in rows {
    let row = row_result?;
    // get a column value by position (0-based)
    let ename: String = row.get(0)?;
    // get a column by name (case-insensitive)
    let sal: i32 = row.get("sal")?;
    // Use `Option<...>` to get a nullable column.
    // Otherwise, `Err(Error::NullValue)` is returned
    // for null values.
    let comm: Option<i32> = row.get(2)?;

    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])?;
for row_result in rows {
    let (ename, sal, comm) = row_result?;
    println!(" {:14}| {:>10}    | {:>10}    |",
             ename,
             sal,
             comm.map_or("".to_string(), |v| v.to_string()));
}

Executes select statements and get the first rows:

use oracle::Connection;

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

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

// Print the first row.
let row = conn.query_row(sql, &[&7369])?;
let ename: String = row.get("empno")?;
let sal: i32 = row.get("sal")?;
let comm: Option<i32> = row.get("comm")?;
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(Error::NoDataFound)`.

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

Executes non-select statements:

use oracle::Connection;

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

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

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

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

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

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

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

Prints column information:

use oracle::Connection;

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

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

// 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:

use oracle::Connection;

let conn = Connection::connect("scott", "tiger", "//localhost/XE")?;

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

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:

use oracle::Connection;

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

// 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", &[])?;
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", &[])?;
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
• Better Oracle object type support

License

Rust-oracle and ODPI-C bundled in rust-oracle are 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.