Struct rusqlite::Savepoint

[+] Show declaration

pub struct Savepoint<'conn> { /* fields omitted */ }

[−] Expand description

Represents a savepoint on a database connection.

Note

Savepoints will roll back by default. Use commit method to explicitly commit the savepoint, or use set_drop_behavior to change what happens when the savepoint is dropped.

Example

fn perform_queries(conn: &mut Connection) -> Result<()> {
    let sp = conn.savepoint()?;

    do_queries_part_1(&sp)?; // sp causes rollback if this fails
    do_queries_part_2(&sp)?; // sp causes rollback if this fails

    sp.commit()
}

Methods

impl<'_> Savepoint<'_>[−]

pub fn new(conn: &mut Connection) -> Result<Savepoint>[−]

Begin a new savepoint. Can be nested.

pub fn with_name<T: Into<String>>(
    conn: &mut Connection,
    name: T
) -> Result<Savepoint>[−]

Begin a new savepoint with a user-provided savepoint name.

pub fn savepoint(&mut self) -> Result<Savepoint>[−]

Begin a nested savepoint.

pub fn savepoint_with_name<T: Into<String>>(
    &mut self,
    name: T
) -> Result<Savepoint>[−]

Begin a nested savepoint with a user-provided savepoint name.

pub fn drop_behavior(&self) -> DropBehavior[−]

Get the current setting for what happens to the savepoint when it is dropped.

pub fn set_drop_behavior(&mut self, drop_behavior: DropBehavior)[−]

Configure the savepoint to perform the specified action when it is dropped.

pub fn commit(self) -> Result<()>[−]

A convenience method which consumes and commits a savepoint.

pub fn rollback(&mut self) -> Result<()>[−]

A convenience method which rolls back a savepoint.

Note

Unlike Transactions, savepoints remain active after they have been rolled back, and can be rolled back again or committed.

pub fn finish(self) -> Result<()>[−]

Consumes the savepoint, committing or rolling back according to the current setting (see drop_behavior).

Functionally equivalent to the Drop implementation, but allows callers to see any errors that occur.

Methods from Deref<Target = Connection>

pub fn busy_timeout(&self, timeout: Duration) -> Result<()>[−]

Set a busy handler that sleeps for a specified amount of time when a table is locked. The handler will sleep multiple times until at least "ms" milliseconds of sleeping have accumulated.

Calling this routine with an argument equal to zero turns off all busy handlers.

There can only be a single busy handler for a particular database connection at any given moment. If another busy handler was defined (using busy_handler) prior to calling this routine, that other busy handler is cleared.

pub fn busy_handler(&self, callback: Option<fn(_: i32) -> bool>) -> Result<()>[−]

Register a callback to handle SQLITE_BUSY errors.

If the busy callback is None, then SQLITE_BUSY is returned immediately upon encountering the lock. The argument to the busy handler callback is the number of times that the busy handler has been invoked previously for the same locking event. If the busy callback returns false, then no additional attempts are made to access the database and SQLITE_BUSY is returned to the application. If the callback returns true, then another attempt is made to access the database and the cycle repeats.

There can only be a single busy handler defined for each database connection. Setting a new busy handler clears any previously set handler. Note that calling busy_timeout() or evaluating PRAGMA busy_timeout=N will change the busy handler and thus clear any previously set busy handler.

pub fn prepare_cached(&self, sql: &str) -> Result<CachedStatement>[−]

Prepare a SQL statement for execution, returning a previously prepared (but not currently in-use) statement if one is available. The returned statement will be cached for reuse by future calls to prepare_cached once it is dropped.

fn insert_new_people(conn: &Connection) -> Result<()> {
    {
        let mut stmt = conn.prepare_cached("INSERT INTO People (name) VALUES (?)")?;
        stmt.execute(&["Joe Smith"])?;
    }
    {
        // This will return the same underlying SQLite statement handle without
        // having to prepare it again.
        let mut stmt = conn.prepare_cached("INSERT INTO People (name) VALUES (?)")?;
        stmt.execute(&["Bob Jones"])?;
    }
    Ok(())
}

Failure

Will return Err if sql cannot be converted to a C-compatible string or if the underlying SQLite call fails.

pub fn set_prepared_statement_cache_capacity(&self, capacity: usize)[−]

Set the maximum number of cached prepared statements this connection will hold. By default, a connection will hold a relatively small number of cached statements. If you need more, or know that you will not use cached statements, you can set the capacity manually using this method.

pub fn flush_prepared_statement_cache(&self)[−]

Remove/finalize all prepared statements currently in the cache.

pub fn db_config(&self, config: DbConfig) -> Result<bool>[−]

Returns the current value of a config.

• SQLITE_DBCONFIG_ENABLE_FKEY: return false or true to indicate whether FK enforcement is off or on
• SQLITE_DBCONFIG_ENABLE_TRIGGER: return false or true to indicate whether triggers are disabled or enabled
• SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER: return false or true to indicate whether fts3_tokenizer are disabled or enabled
• SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE: return false to indicate checkpoints-on-close are not disabled or true if they are
• SQLITE_DBCONFIG_ENABLE_QPSG: return false or true to indicate whether the QPSG is disabled or enabled
• SQLITE_DBCONFIG_TRIGGER_EQP: return false to indicate output-for-trigger are not disabled or true if it is

pub fn set_db_config(&self, config: DbConfig, new_val: bool) -> Result<bool>[−]

Make configuration changes to a database connection

• SQLITE_DBCONFIG_ENABLE_FKEY: false to disable FK enforcement, true to enable FK enforcement
• SQLITE_DBCONFIG_ENABLE_TRIGGER: false to disable triggers, true to enable triggers
• SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER: false to disable fts3_tokenizer(), true to enable fts3_tokenizer()
• SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE: false (the default) to enable checkpoints-on-close, true to disable them
• SQLITE_DBCONFIG_ENABLE_QPSG: false to disable the QPSG, true to enable QPSG
• SQLITE_DBCONFIG_TRIGGER_EQP: false to disable output for trigger programs, true to enable it

pub fn pragma_query_value<T, F>(
    &self,
    schema_name: Option<DatabaseName>,
    pragma_name: &str,
    f: F
) -> Result<T> where
    F: FnOnce(&Row) -> Result<T>, [−]

Query the current value of pragma_name.

Some pragmas will return multiple rows/values which cannot be retrieved with this method.

Prefer PRAGMA function introduced in SQLite 3.20: SELECT user_version FROM pragma_user_version;

pub fn pragma_query<F>(
    &self,
    schema_name: Option<DatabaseName>,
    pragma_name: &str,
    f: F
) -> Result<()> where
    F: FnMut(&Row) -> Result<()>, [−]

Query the current rows/values of pragma_name.

Prefer PRAGMA function introduced in SQLite 3.20: SELECT * FROM pragma_collation_list;

pub fn pragma<F>(
    &self,
    schema_name: Option<DatabaseName>,
    pragma_name: &str,
    pragma_value: &dyn ToSql,
    f: F
) -> Result<()> where
    F: FnMut(&Row) -> Result<()>, [−]

Query the current value(s) of pragma_name associated to pragma_value.

This method can be used with query-only pragmas which need an argument (e.g. table_info('one_tbl')) or pragmas which returns value(s) (e.g. integrity_check).

Prefer PRAGMA function introduced in SQLite 3.20: SELECT * FROM pragma_table_info(?);

pub fn pragma_update(
    &self,
    schema_name: Option<DatabaseName>,
    pragma_name: &str,
    pragma_value: &dyn ToSql
) -> Result<()>[−]

Set a new value to pragma_name.

Some pragmas will return the updated value which cannot be retrieved with this method.

pub fn pragma_update_and_check<F, T>(
    &self,
    schema_name: Option<DatabaseName>,
    pragma_name: &str,
    pragma_value: &dyn ToSql,
    f: F
) -> Result<T> where
    F: FnOnce(&Row) -> Result<T>, [−]

Set a new value to pragma_name and return the updated value.

Only few pragmas automatically return the updated value.

pub fn execute_batch(&self, sql: &str) -> Result<()>[−]

Convenience method to run multiple SQL statements (that cannot take any parameters).

Uses sqlite3_exec under the hood.

Example

fn create_tables(conn: &Connection) -> Result<()> {
    conn.execute_batch(
        "BEGIN;
                        CREATE TABLE foo(x INTEGER);
                        CREATE TABLE bar(y TEXT);
                        COMMIT;",
    )
}

Failure

Will return Err if sql cannot be converted to a C-compatible string or if the underlying SQLite call fails.

pub fn execute<P>(&self, sql: &str, params: P) -> Result<usize> where
    P: IntoIterator,
    P::Item: ToSql, [−]

Convenience method to prepare and execute a single SQL statement.

On success, returns the number of rows that were changed or inserted or deleted (via sqlite3_changes).

Example

fn update_rows(conn: &Connection) {
    match conn.execute("UPDATE foo SET bar = 'baz' WHERE qux = ?", &[1i32]) {
        Ok(updated) => println!("{} rows were updated", updated),
        Err(err) => println!("update failed: {}", err),
    }
}

Failure

Will return Err if sql cannot be converted to a C-compatible string or if the underlying SQLite call fails.

pub fn execute_named(
    &self,
    sql: &str,
    params: &[(&str, &dyn ToSql)]
) -> Result<usize>[−]

Convenience method to prepare and execute a single SQL statement with named parameter(s).

On success, returns the number of rows that were changed or inserted or deleted (via sqlite3_changes).

Example

fn insert(conn: &Connection) -> Result<usize> {
    conn.execute_named(
        "INSERT INTO test (name) VALUES (:name)",
        &[(":name", &"one")],
    )
}

Failure

Will return Err if sql cannot be converted to a C-compatible string or if the underlying SQLite call fails.

pub fn last_insert_rowid(&self) -> i64[−]

Get the SQLite rowid of the most recent successful INSERT.

Uses sqlite3_last_insert_rowid under the hood.

pub fn query_row<T, P, F>(&self, sql: &str, params: P, f: F) -> Result<T> where
    P: IntoIterator,
    P::Item: ToSql,
    F: FnOnce(&Row) -> Result<T>, [−]

Convenience method to execute a query that is expected to return a single row.

Example

fn preferred_locale(conn: &Connection) -> Result<String> {
    conn.query_row(
        "SELECT value FROM preferences WHERE name='locale'",
        NO_PARAMS,
        |row| row.get(0),
    )
}

If the query returns more than one row, all rows except the first are ignored.

Returns Err(QueryReturnedNoRows) if no results are returned. If the query truly is optional, you can call .optional() on the result of this to get a Result<Option<T>>.

Failure

Will return Err if sql cannot be converted to a C-compatible string or if the underlying SQLite call fails.

pub fn query_row_named<T, F>(
    &self,
    sql: &str,
    params: &[(&str, &dyn ToSql)],
    f: F
) -> Result<T> where
    F: FnOnce(&Row) -> Result<T>, [−]

Convenience method to execute a query with named parameter(s) that is expected to return a single row.

If the query returns more than one row, all rows except the first are ignored.

Returns Err(QueryReturnedNoRows) if no results are returned. If the query truly is optional, you can call .optional() on the result of this to get a Result<Option<T>>.

Failure

Will return Err if sql cannot be converted to a C-compatible string or if the underlying SQLite call fails.

pub fn query_row_and_then<T, E, P, F>(
    &self,
    sql: &str,
    params: P,
    f: F
) -> Result<T, E> where
    P: IntoIterator,
    P::Item: ToSql,
    F: FnOnce(&Row) -> Result<T, E>,
    E: From<Error>, [−]

Convenience method to execute a query that is expected to return a single row, and execute a mapping via f on that returned row with the possibility of failure. The Result type of f must implement std::convert::From<Error>.

Example

fn preferred_locale(conn: &Connection) -> Result<String> {
    conn.query_row_and_then(
        "SELECT value FROM preferences WHERE name='locale'",
        NO_PARAMS,
        |row| row.get(0),
    )
}

If the query returns more than one row, all rows except the first are ignored.

Failure

Will return Err if sql cannot be converted to a C-compatible string or if the underlying SQLite call fails.

pub fn prepare(&self, sql: &str) -> Result<Statement>[−]

Prepare a SQL statement for execution.

Example

fn insert_new_people(conn: &Connection) -> Result<()> {
    let mut stmt = conn.prepare("INSERT INTO People (name) VALUES (?)")?;
    stmt.execute(&["Joe Smith"])?;
    stmt.execute(&["Bob Jones"])?;
    Ok(())
}

Failure

Will return Err if sql cannot be converted to a C-compatible string or if the underlying SQLite call fails.

pub unsafe fn handle(&self) -> *mut sqlite3[−]

Get access to the underlying SQLite database connection handle.

Warning

You should not need to use this function. If you do need to, please open an issue on the rusqlite repository and describe your use case.

Safety

This function is unsafe because it gives you raw access to the SQLite connection, and what you do with it could impact the safety of this Connection.

pub fn get_interrupt_handle(&self) -> InterruptHandle[−]

Get access to a handle that can be used to interrupt long running queries from another thread.

pub fn is_autocommit(&self) -> bool[−]

Test for auto-commit mode. Autocommit mode is on by default.

pub fn is_busy(&self) -> bool[−]

Determine if all associated prepared statements have been reset.

Trait Implementations

impl<'_> Deref for Savepoint<'_>[+]

[+] Show hidden undocumented items

type Target = Connection

The resulting type after dereferencing.

fn deref(&self) -> &Connection[−]

Dereferences the value.

impl<'_> Drop for Savepoint<'_>[+]

[+] Show hidden undocumented items

fn drop(&mut self)[−]

Executes the destructor for this type.