Crates.io | mysql |
lib.rs | mysql |
version | 25.0.1 |
source | src |
created_at | 2014-11-24 18:05:48.308665 |
updated_at | 2024-05-21 11:11:56.33017 |
description | Mysql client library implemented in rust |
homepage | |
repository | https://github.com/blackbeam/rust-mysql-simple |
max_upload_size | |
id | 385 |
size | 421,506 |
This crate offers:
Features:
Opts::get_enable_cleartext_plugin
].Put the desired version of the crate into the dependencies
section of your Cargo.toml
:
[dependencies]
mysql = "*"
use mysql::*;
use mysql::prelude::*;
#[derive(Debug, PartialEq, Eq)]
struct Payment {
customer_id: i32,
amount: i32,
account_name: Option<String>,
}
fn main() -> std::result::Result<(), Box<dyn std::error::Error>> {
let url = "mysql://root:password@localhost:3307/db_name";
# Opts::try_from(url)?;
# let url = get_opts();
let pool = Pool::new(url)?;
let mut conn = pool.get_conn()?;
// Let's create a table for payments.
conn.query_drop(
r"CREATE TEMPORARY TABLE payment (
customer_id int not null,
amount int not null,
account_name text
)")?;
let payments = vec![
Payment { customer_id: 1, amount: 2, account_name: None },
Payment { customer_id: 3, amount: 4, account_name: Some("foo".into()) },
Payment { customer_id: 5, amount: 6, account_name: None },
Payment { customer_id: 7, amount: 8, account_name: None },
Payment { customer_id: 9, amount: 10, account_name: Some("bar".into()) },
];
// Now let's insert payments to the database
conn.exec_batch(
r"INSERT INTO payment (customer_id, amount, account_name)
VALUES (:customer_id, :amount, :account_name)",
payments.iter().map(|p| params! {
"customer_id" => p.customer_id,
"amount" => p.amount,
"account_name" => &p.account_name,
})
)?;
// Let's select payments from database. Type inference should do the trick here.
let selected_payments = conn
.query_map(
"SELECT customer_id, amount, account_name from payment",
|(customer_id, amount, account_name)| {
Payment { customer_id, amount, account_name }
},
)?;
// Let's make sure, that `payments` equals to `selected_payments`.
// Mysql gives no guaranties on order of returned rows
// without `ORDER BY`, so assume we are lucky.
assert_eq!(payments, selected_payments);
println!("Yay!");
Ok(())
}
feature sets:
mysql_common
features, native-tls
, buffer-pool
,
flate2/zlib
and derive
default
but with rustls-tls
instead of native-tls
and flate2/rust_backend
instead of flate2/zlib
flate2/zlib
crate's features:
native-tls
as the TLS backend
(see the SSL Support section)rustls
as the TLS backend
(see the SSL Support section)prelude
external features enabled by default:
for the flate2
crate (please consult flate2
crate documentation for available features):
zlib
backend is chosed by default.for the mysql_common
crate (please consult mysql_common
crate documentation for available features):
bigdecimal03
is enabled by defaultrust_decimal
is enabled by defaulttime03
is enabled by defaultuuid
is enabled by defaultfrunk
is enabled by defaultPlease note, that you'll need to reenable required features if you are using default-features = false
:
[dependencies]
# Lets say that we want to use the `rustls-tls` feature:
mysql = { version = "*", default-features = false, features = ["minimal", "rustls-tls"] }
# Previous line disables default mysql features,
# so now we need to choose desired mysql_common features:
mysql_common = { version = "*", default-features = false, features = ["bigdecimal03", "time03", "uuid"]}
Please refer to the crate docs.
Opts
This structure holds server host name, client username/password and other settings, that controls client behavior.
Note, that you can use URL-based connection string as a source of an Opts
instance.
URL schema must be mysql
. Host, port and credentials, as well as query parameters,
should be given in accordance with the RFC 3986.
Examples:
let _ = Opts::from_url("mysql://localhost/some_db")?;
let _ = Opts::from_url("mysql://[::1]/some_db")?;
let _ = Opts::from_url("mysql://user:pass%20word@127.0.0.1:3307/some_db?")?;
Supported URL parameters (for the meaning of each field please refer to the docs on Opts
structure in the create API docs):
user: string
– MySql client user namepassword: string
– MySql client password;db_name: string
– MySql database name;host: Host
– MySql server hostname/ip;port: u16
– MySql server port;pool_min: usize
– see [PoolConstraints::min
];pool_max: usize
– see [PoolConstraints::max
];prefer_socket: true | false
- see [Opts::get_prefer_socket
];tcp_keepalive_time_ms: u32
- defines the value (in milliseconds)
of the tcp_keepalive_time
field in the Opts
structure;tcp_keepalive_probe_interval_secs: u32
- defines the value
of the tcp_keepalive_probe_interval_secs
field in the Opts
structure;tcp_keepalive_probe_count: u32
- defines the value
of the tcp_keepalive_probe_count
field in the Opts
structure;tcp_connect_timeout_ms: u64
- defines the value (in milliseconds)
of the tcp_connect_timeout
field in the Opts
structure;tcp_user_timeout_ms
- defines the value (in milliseconds)
of the tcp_user_timeout
field in the Opts
structure;stmt_cache_size: u32
- defines the value of the same field in the Opts
structure;enable_cleartext_plugin
– see [Opts::get_enable_cleartext_plugin
];secure_auth
– see [Opts::get_secure_auth
];reset_connection
– see [PoolOpts::reset_connection
];check_health
– see [PoolOpts::check_health
];compress
- defines the value of the same field in the Opts
structure.
Supported value are:
true
- enables compression with the default compression level;fast
- enables compression with "fast" compression level;best
- enables compression with "best" compression level;1
..9
- enables compression with the given compression level.socket
- socket path on UNIX, or pipe name on Windows.OptsBuilder
It's a convenient builder for the Opts
structure. It defines setters for fields
of the Opts
structure.
let opts = OptsBuilder::new()
.user(Some("foo"))
.db_name(Some("bar"));
let _ = Conn::new(opts)?;
Conn
This structure represents an active MySql connection. It also holds statement cache and metadata for the last result set.
Conn's destructor will gracefully disconnect it from the server.
Transaction
It's a simple wrapper on top of a routine, that starts with START TRANSACTION
and ends with COMMIT
or ROLLBACK
.
use mysql::*;
use mysql::prelude::*;
let pool = Pool::new(get_opts())?;
let mut conn = pool.get_conn()?;
let mut tx = conn.start_transaction(TxOpts::default())?;
tx.query_drop("CREATE TEMPORARY TABLE tmp (TEXT a)")?;
tx.exec_drop("INSERT INTO tmp (a) VALUES (?)", ("foo",))?;
let val: Option<String> = tx.query_first("SELECT a from tmp")?;
assert_eq!(val.unwrap(), "foo");
// Note, that transaction will be rolled back implicitly on Drop, if not committed.
tx.rollback();
let val: Option<String> = conn.query_first("SELECT a from tmp")?;
assert_eq!(val, None);
Pool
It's a reference to a connection pool, that can be cloned and shared between threads.
use mysql::*;
use mysql::prelude::*;
use std::thread::spawn;
let pool = Pool::new(get_opts())?;
let handles = (0..4).map(|i| {
spawn({
let pool = pool.clone();
move || {
let mut conn = pool.get_conn()?;
conn.exec_first::<u32, _, _>("SELECT ? * 10", (i,))
.map(Option::unwrap)
}
})
});
let result: Result<Vec<u32>> = handles.map(|handle| handle.join().unwrap()).collect();
assert_eq!(result.unwrap(), vec![0, 10, 20, 30]);
Statement
Statement, actually, is just an identifier coupled with statement metadata, i.e an information
about its parameters and columns. Internally the Statement
structure also holds additional
data required to support named parameters (see bellow).
use mysql::*;
use mysql::prelude::*;
let pool = Pool::new(get_opts())?;
let mut conn = pool.get_conn()?;
let stmt = conn.prep("DO ?")?;
// The prepared statement will return no columns.
assert!(stmt.columns().is_empty());
// The prepared statement have one parameter.
let param = stmt.params().get(0).unwrap();
assert_eq!(param.schema_str(), "");
assert_eq!(param.table_str(), "");
assert_eq!(param.name_str(), "?");
Value
This enumeration represents the raw value of a MySql cell. Library offers conversion between
Value
and different rust types via FromValue
trait described below.
FromValue
traitThis trait is reexported from mysql_common create. Please refer to its crate docs for the list of supported conversions.
Trait offers conversion in two flavours:
from_value(Value) -> T
- convenient, but panicking conversion.
Note, that for any variant of Value
there exist a type, that fully covers its domain,
i.e. for any variant of Value
there exist T: FromValue
such that from_value
will never
panic. This means, that if your database schema is known, than it's possible to write your
application using only from_value
with no fear of runtime panic.
from_value_opt(Value) -> Option<T>
- non-panicking, but less convenient conversion.
This function is useful to probe conversion in cases, where source database schema is unknown.
use mysql::*;
use mysql::prelude::*;
let via_test_protocol: u32 = from_value(Value::Bytes(b"65536".to_vec()));
let via_bin_protocol: u32 = from_value(Value::UInt(65536));
assert_eq!(via_test_protocol, via_bin_protocol);
let unknown_val = // ...
// Maybe it is a float?
let unknown_val = match from_value_opt::<f64>(unknown_val) {
Ok(float) => {
println!("A float value: {}", float);
return Ok(());
}
Err(FromValueError(unknown_val)) => unknown_val,
};
// Or a string?
let unknown_val = match from_value_opt::<String>(unknown_val) {
Ok(string) => {
println!("A string value: {}", string);
return Ok(());
}
Err(FromValueError(unknown_val)) => unknown_val,
};
// Screw this, I'll simply match on it
match unknown_val {
val @ Value::NULL => {
println!("An empty value: {:?}", from_value::<Option<u8>>(val))
},
val @ Value::Bytes(..) => {
// It's non-utf8 bytes, since we already tried to convert it to String
println!("Bytes: {:?}", from_value::<Vec<u8>>(val))
}
val @ Value::Int(..) => {
println!("A signed integer: {}", from_value::<i64>(val))
}
val @ Value::UInt(..) => {
println!("An unsigned integer: {}", from_value::<u64>(val))
}
Value::Float(..) => unreachable!("already tried"),
val @ Value::Double(..) => {
println!("A double precision float value: {}", from_value::<f64>(val))
}
val @ Value::Date(..) => {
use time::PrimitiveDateTime;
println!("A date value: {}", from_value::<PrimitiveDateTime>(val))
}
val @ Value::Time(..) => {
use std::time::Duration;
println!("A time value: {:?}", from_value::<Duration>(val))
}
}
Row
Internally Row
is a vector of Value
s, that also allows indexing by a column name/offset,
and stores row metadata. Library offers conversion between Row
and sequences of Rust types
via FromRow
trait described below.
FromRow
traitThis trait is reexported from mysql_common create. Please refer to its crate docs for the list of supported conversions.
This conversion is based on the FromValue
and so comes in two similar flavours:
from_row(Row) -> T
- same as from_value
, but for rows;from_row_opt(Row) -> Option<T>
- same as from_value_opt
, but for rows.Queryable
trait offers implicit conversion for rows of a query result,
that is based on this trait.
use mysql::*;
use mysql::prelude::*;
let mut conn = Conn::new(get_opts())?;
// Single-column row can be converted to a singular value:
let val: Option<String> = conn.query_first("SELECT 'foo'")?;
assert_eq!(val.unwrap(), "foo");
// Example of a mutli-column row conversion to an inferred type:
let row = conn.query_first("SELECT 255, 256")?;
assert_eq!(row, Some((255u8, 256u16)));
// The FromRow trait does not support to-tuple conversion for rows with more than 12 columns,
// but you can do this by hand using row indexing or `Row::take` method:
let row: Row = conn.exec_first("select 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12", ())?.unwrap();
for i in 0..row.len() {
assert_eq!(row[i], Value::Int(i as i64));
}
// Another way to handle wide rows is to use HList (requires `mysql_common/frunk` feature)
use frunk::{HList, hlist, hlist_pat};
let query = "select 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15";
type RowType = HList!(u8, u16, u32, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8, u8);
let first_three_columns = conn.query_map(query, |row: RowType| {
// do something with the row (see the `frunk` crate documentation)
let hlist_pat![c1, c2, c3, ...] = row;
(c1, c2, c3)
});
assert_eq!(first_three_columns.unwrap(), vec![(0_u8, 1_u16, 2_u32)]);
// Some unknown row
let row: Row = conn.query_first(
// ...
# "SELECT 255, Null",
)?.unwrap();
for column in row.columns_ref() {
// Cells in a row can be indexed by numeric index or by column name
let column_value = &row[column.name_str().as_ref()];
println!(
"Column {} of type {:?} with value {:?}",
column.name_str(),
column.column_type(),
column_value,
);
}
Params
Represents parameters of a prepared statement, but this type won't appear directly in your code
because binary protocol API will ask for T: Into<Params>
, where Into<Params>
is implemented:
for tuples of Into<Value>
types up to arity 12;
Note: singular tuple requires extra comma, e.g. ("foo",)
;
for IntoIterator<Item: Into<Value>>
for cases, when your statement takes more
than 12 parameters;
for named parameters representation (the value of the params!
macro, described below).
use mysql::*;
use mysql::prelude::*;
let mut conn = Conn::new(get_opts())?;
// Singular tuple requires extra comma:
let row: Option<u8> = conn.exec_first("SELECT ?", (0,))?;
assert_eq!(row.unwrap(), 0);
// More than 12 parameters:
let row: Option<u8> = conn.exec_first(
"SELECT CONVERT(? + ? + ? + ? + ? + ? + ? + ? + ? + ? + ? + ? + ? + ? + ? + ?, UNSIGNED)",
(0..16).collect::<Vec<_>>(),
)?;
assert_eq!(row.unwrap(), 120);
Note: Please refer to the mysql_common crate docs for the list
of types, that implements Into<Value>
.
Serialized
, Deserialized
Wrapper structures for cases, when you need to provide a value for a JSON cell, or when you need to parse JSON cell as a struct.
use mysql::*;
use mysql::prelude::*;
/// Serializable structure.
#[derive(Debug, PartialEq, Serialize, Deserialize)]
struct Example {
foo: u32,
}
// Value::from for Serialized will emit json string.
let value = Value::from(Serialized(Example { foo: 42 }));
assert_eq!(value, Value::Bytes(br#"{"foo":42}"#.to_vec()));
// from_value for Deserialized will parse json string.
let structure: Deserialized<Example> = from_value(value);
assert_eq!(structure, Deserialized(Example { foo: 42 }));
QueryResult
]It's an iterator over rows of a query result with support of multi-result sets. It's intended
for cases when you need full control during result set iteration. For other cases
Queryable
provides a set of methods that will immediately consume
the first result set and drop everything else.
This iterator is lazy so it won't read the result from server until you iterate over it.
MySql protocol is strictly sequential, so Conn
will be mutably borrowed until the result
is fully consumed (please also look at [QueryResult::iter
] docs).
use mysql::*;
use mysql::prelude::*;
let mut conn = Conn::new(get_opts())?;
// This query will emit two result sets.
let mut result = conn.query_iter("SELECT 1, 2; SELECT 3, 3.14;")?;
let mut sets = 0;
while let Some(result_set) = result.iter() {
sets += 1;
println!("Result set columns: {:?}", result_set.columns());
println!(
"Result set meta: {}, {:?}, {} {}",
result_set.affected_rows(),
result_set.last_insert_id(),
result_set.warnings(),
result_set.info_str(),
);
for row in result_set {
match sets {
1 => {
// First result set will contain two numbers.
assert_eq!((1_u8, 2_u8), from_row(row?));
}
2 => {
// Second result set will contain a number and a float.
assert_eq!((3_u8, 3.14), from_row(row?));
}
_ => unreachable!(),
}
}
}
assert_eq!(sets, 2);
MySql text protocol is implemented in the set of Queryable::query*
methods. It's useful when your
query doesn't have parameters.
Note: All values of a text protocol result set will be encoded as strings by the server,
so from_value
conversion may lead to additional parsing costs.
Examples:
let pool = Pool::new(get_opts())?;
let val = pool.get_conn()?.query_first("SELECT POW(2, 16)")?;
// Text protocol returns bytes even though the result of POW
// is actually a floating point number.
assert_eq!(val, Some(Value::Bytes("65536".as_bytes().to_vec())));
TextQuery
trait.The TextQuery
trait covers the set of Queryable::query*
methods from the perspective
of a query, i.e. TextQuery
is something, that can be performed if suitable connection
is given. Suitable connections are:
&Pool
Conn
PooledConn
&mut Conn
&mut PooledConn
&mut Transaction
The unique characteristic of this trait, is that you can give away the connection
and thus produce QueryResult
that satisfies 'static
:
use mysql::*;
use mysql::prelude::*;
fn iter(pool: &Pool) -> Result<impl Iterator<Item=Result<u32>>> {
let result = "SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3".run(pool)?;
Ok(result.map(|row| row.map(from_row)))
}
let pool = Pool::new(get_opts())?;
let it = iter(&pool)?;
assert_eq!(it.collect::<Result<Vec<u32>>>()?, vec![1, 2, 3]);
MySql binary protocol is implemented in prep
, close
and the set of exec*
methods,
defined on the Queryable
trait. Prepared statements is the only way to
pass rust value to the MySql server. MySql uses ?
symbol as a parameter placeholder
and it's only possible to use parameters where a single MySql value is expected.
For example:
let pool = Pool::new(get_opts())?;
let val = pool.get_conn()?.exec_first("SELECT POW(?, ?)", (2, 16))?;
assert_eq!(val, Some(Value::Double(65536.0)));
In MySql each prepared statement belongs to a particular connection and can't be executed
on another connection. Trying to do so will lead to an error. The driver won't tie statement
to its connection in any way, but one can look on to the connection id, contained
in the Statement
structure.
let pool = Pool::new(get_opts())?;
let mut conn_1 = pool.get_conn()?;
let mut conn_2 = pool.get_conn()?;
let stmt_1 = conn_1.prep("SELECT ?")?;
// stmt_1 is for the conn_1, ..
assert!(stmt_1.connection_id() == conn_1.connection_id());
assert!(stmt_1.connection_id() != conn_2.connection_id());
// .. so stmt_1 will execute only on conn_1
assert!(conn_1.exec_drop(&stmt_1, ("foo",)).is_ok());
assert!(conn_2.exec_drop(&stmt_1, ("foo",)).is_err());
Statemet cache only works for:
Conn
]PooledConn
]:
PoolOpts::reset_connection
] is true
Conn
] if [PoolOpts::reset_connection
] is false
Conn
will manage the cache of prepared statements on the client side, so subsequent calls
to prepare with the same statement won't lead to a client-server roundtrip. Cache size
for each connection is determined by the stmt_cache_size
field of the Opts
structure.
Statements, that are out of this boundary will be closed in LRU order.
Statement cache is completely disabled if stmt_cache_size
is zero.
Caveats:
disabled statement cache means, that you have to close statements yourself using
Conn::close
, or they'll exhaust server limits/resources;
you should be aware of the max_prepared_stmt_count
option of the MySql server. If the number of active connections times the value
of stmt_cache_size
is greater, than you could receive an error while prepareing
another statement.
MySql itself doesn't have named parameters support, so it's implemented on the client side.
One should use :name
as a placeholder syntax for a named parameter. Named parameters uses
the following naming convention:
_
or a..z
_
, a..z
and 0..9
Named parameters may be repeated within the statement, e.g SELECT :foo, :foo
will require
a single named parameter foo
that will be repeated on the corresponding positions during
statement execution.
One should use the params!
macro to build parameters for execution.
Note: Positional and named parameters can't be mixed within the single statement.
Examples:
let pool = Pool::new(get_opts())?;
let mut conn = pool.get_conn()?;
let stmt = conn.prep("SELECT :foo, :bar, :foo")?;
let foo = 42;
let val_13 = conn.exec_first(&stmt, params! { "foo" => 13, "bar" => foo })?.unwrap();
// Short syntax is available when param name is the same as variable name:
let val_42 = conn.exec_first(&stmt, params! { foo, "bar" => 13 })?.unwrap();
assert_eq!((foo, 13, foo), val_42);
assert_eq!((13, foo, 13), val_13);
Crate uses the global lock-free buffer pool for the purpose of IO and data serialization/deserialization, that helps to avoid allocations for basic scenarios. You can control it's characteristics using the following environment variables:
RUST_MYSQL_BUFFER_POOL_CAP
(defaults to 128) – controls the pool capacity. Dropped buffer will
be immediately deallocated if the pool is full. Set it to 0
to disable the pool at runtime.
RUST_MYSQL_BUFFER_SIZE_CAP
(defaults to 4MiB) – controls the maximum capacity of a buffer
stored in the pool. Capacity of a dropped buffer will be shrunk to this value when buffer
is returned to the pool.
To completely disable the pool (say you are using jemalloc) please remove the buffer-pool
feature
from the set of default crate features (see the Crate Features section).
BinQuery
and BatchQuery
traits.BinQuery
and BatchQuery
traits covers the set of Queryable::exec*
methods from
the perspective of a query, i.e. BinQuery
is something, that can be performed if suitable
connection is given (see TextQuery
section for the list
of suitable connections).
As with the TextQuery
you can give away the connection and acquire
QueryResult
that satisfies 'static
.
BinQuery
is for prepared statements, and prepared statements requires a set of parameters,
so BinQuery
is implemented for QueryWithParams
structure, that can be acquired, using
WithParams
trait.
Example:
use mysql::*;
use mysql::prelude::*;
let pool = Pool::new(get_opts())?;
let result: Option<(u8, u8, u8)> = "SELECT ?, ?, ?"
.with((1, 2, 3)) // <- WithParams::with will construct an instance of QueryWithParams
.first(&pool)?; // <- QueryWithParams is executed on the given pool
assert_eq!(result.unwrap(), (1, 2, 3));
The BatchQuery
trait is a helper for batch statement execution. It's implemented for
QueryWithParams
where parameters is an iterator over parameters:
use mysql::*;
use mysql::prelude::*;
let pool = Pool::new(get_opts())?;
let mut conn = pool.get_conn()?;
"CREATE TEMPORARY TABLE batch (x INT)".run(&mut conn)?;
"INSERT INTO batch (x) VALUES (?)"
.with((0..3).map(|x| (x,))) // <- QueryWithParams constructed with an iterator
.batch(&mut conn)?; // <- batch execution is preformed here
let result: Vec<u8> = "SELECT x FROM batch".fetch(conn)?;
assert_eq!(result, vec![0, 1, 2]);
Queryable
The Queryable
trait defines common methods for Conn
, PooledConn
and Transaction
.
The set of basic methods consts of:
query_iter
- basic methods to execute text query and get QueryResult
;prep
- basic method to prepare a statement;exec_iter
- basic method to execute statement and get QueryResult
;close
- basic method to close the statement;The trait also defines the set of helper methods, that is based on basic methods. These methods will consume only the first result set, other result sets will be dropped:
{query|exec}
- to collect the result into a Vec<T: FromRow>
;{query|exec}_first
- to get the first T: FromRow
, if any;{query|exec}_map
- to map each T: FromRow
to some U
;{query|exec}_fold
- to fold the set of T: FromRow
to a single value;{query|exec}_drop
- to immediately drop the result.The trait also defines the exec_batch
function, which is a helper for batch statement
execution.
SSL support comes in two flavors:
Based on native-tls – this is the default option, that usually works without pitfalls
(see the native-tls
crate feature).
Based on rustls – TLS backend written in Rust. Please use the rustls-tls
crate feature
to enable it (see the Crate Features section).
Please also note a few things about rustls:
Available here
Licensed under either of
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.