pub struct TransactionBuilder<'a, C> { /* private fields */ }
Available on crate feature postgres_backend only.
Expand description

Used to build a transaction, specifying additional details.

This struct is returned by .build_transaction. See the documentation for methods on this struct for usage examples. See the PostgreSQL documentation for SET TRANSACTION for details on the behavior of each option.

Implementations§

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impl<'a, C> TransactionBuilder<'a, C>
where C: Connection<Backend = Pg, TransactionManager = AnsiTransactionManager>,

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pub fn new(connection: &'a mut C) -> Self

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Creates a new TransactionBuilder.

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pub fn read_only(self) -> Self

Makes the transaction READ ONLY

§Example
conn.build_transaction()
    .read_only()
    .run::<_, diesel::result::Error, _>(|conn| {
        let read_attempt = users.select(name).load::<String>(conn);
        assert!(read_attempt.is_ok());

        let write_attempt = diesel::insert_into(users)
            .values(name.eq("Ruby"))
            .execute(conn);
        assert!(write_attempt.is_err());

        Ok(())
    })?;
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pub fn read_write(self) -> Self

Makes the transaction READ WRITE

This is the default, unless you’ve changed the default_transaction_read_only configuration parameter.

§Example
conn.build_transaction()
    .read_write()
    .run(|conn| {
        let read_attempt = users.select(name).load::<String>(conn);
        assert!(read_attempt.is_ok());

        let write_attempt = diesel::insert_into(users)
            .values(name.eq("Ruby"))
            .execute(conn);
        assert!(write_attempt.is_ok());

        Ok(())
    })
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pub fn deferrable(self) -> Self

Makes the transaction DEFERRABLE

§Example
conn.build_transaction()
    .deferrable()
    .run(|conn| Ok(()))
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pub fn not_deferrable(self) -> Self

Makes the transaction NOT DEFERRABLE

This is the default, unless you’ve changed the default_transaction_deferrable configuration parameter.

§Example
conn.build_transaction()
    .not_deferrable()
    .run(|conn| Ok(()))
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pub fn read_committed(self) -> Self

Makes the transaction ISOLATION LEVEL READ COMMITTED

This is the default, unless you’ve changed the default_transaction_isolation_level configuration parameter.

§Example
conn.build_transaction()
    .read_committed()
    .run(|conn| Ok(()))
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pub fn repeatable_read(self) -> Self

Makes the transaction ISOLATION LEVEL REPEATABLE READ

§Example
conn.build_transaction()
    .repeatable_read()
    .run(|conn| Ok(()))
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pub fn serializable(self) -> Self

Makes the transaction ISOLATION LEVEL SERIALIZABLE

§Example
conn.build_transaction()
    .serializable()
    .run(|conn| Ok(()))
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pub fn run<T, E, F>(&mut self, f: F) -> Result<T, E>
where F: FnOnce(&mut C) -> Result<T, E>, E: From<Error>,

Runs the given function inside of the transaction with the parameters given to this builder.

This function executes the provided closure f inside a database transaction. If there is already an open transaction for the current connection it will return an error. The connection is committed if the closure returns Ok(_), it will be rolled back if it returns Err(_). For both cases the original result value will be returned from this function.

If the transaction fails to commit and requires a rollback according to Postgres, (e.g. serialization failure) a rollback will be attempted. If the rollback fails, the error will be returned in a Error::RollbackErrorOnCommit, from which you will be able to extract both the original commit error and the rollback error. In addition, the connection will be considered broken as it contains a uncommitted unabortable open transaction. Any further interaction with the transaction system will result in an returned error in this case.

Trait Implementations§

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impl<'a, C> QueryFragment<Pg> for TransactionBuilder<'a, C>

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fn walk_ast<'b>(&'b self, out: AstPass<'_, 'b, Pg>) -> QueryResult<()>

Walk over this QueryFragment for all passes. Read more
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fn to_sql(&self, out: &mut DB::QueryBuilder, backend: &DB) -> QueryResult<()>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.
Converts this QueryFragment to its SQL representation. Read more
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fn collect_binds<'b>( &'b self, out: &mut DB::BindCollector<'b>, metadata_lookup: &mut DB::MetadataLookup, backend: &'b DB ) -> QueryResult<()>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.
Serializes all bind parameters in this query. Read more
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fn is_safe_to_cache_prepared(&self, backend: &DB) -> QueryResult<bool>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.
Is this query safe to store in the prepared statement cache? Read more
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fn is_noop(&self, backend: &DB) -> QueryResult<bool>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.
Does walking this AST have any effect?

Auto Trait Implementations§

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impl<'a, C> Freeze for TransactionBuilder<'a, C>

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impl<'a, C> RefUnwindSafe for TransactionBuilder<'a, C>
where C: RefUnwindSafe,

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impl<'a, C> Send for TransactionBuilder<'a, C>
where C: Send,

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impl<'a, C> Sync for TransactionBuilder<'a, C>
where C: Sync,

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impl<'a, C> Unpin for TransactionBuilder<'a, C>

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impl<'a, C> !UnwindSafe for TransactionBuilder<'a, C>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoSql for T

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fn into_sql<T>(self) -> AsExprOf<Self, T>

Convert self to an expression for Diesel’s query builder. Read more
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fn as_sql<'a, T>(&'a self) -> AsExprOf<&'a Self, T>

Convert &self to an expression for Diesel’s query builder. Read more
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impl<T, DB> QueryFragmentForCachedStatement<DB> for T
where DB: Backend, <DB as Backend>::QueryBuilder: Default, T: QueryFragment<DB>,

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fn construct_sql(&self, backend: &DB) -> Result<String, Error>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.
Convert the query fragment into a SQL string for the given backend
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fn is_safe_to_cache_prepared(&self, backend: &DB) -> Result<bool, Error>

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.
Check whether it’s safe to cache the query
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V