Struct persy::Transaction [−][src]
pub struct Transaction { /* fields omitted */ }
Expand description
Transaction container, it include all the changes done in a transaction.
Implementations
Create a new segment with the provided name
Example
let mut tx = persy.begin()?;
tx.create_segment("my_new_segment")?;
tx.prepare()?.commit()?;
Drop a existing segment
Example
let mut tx = persy.begin()?;
tx.drop_segment("existing_segment_name")?;
tx.prepare()?.commit()?;
Check if a segment already exist in the storage considering the transaction
Example
let mut tx = persy.begin()?;
tx.create_segment("my_new_segment")?;
assert!(tx.exists_segment("my_new_segment")?);
pub fn solve_segment_id(
&self,
segment: impl ToSegmentId
) -> Result<SegmentId, PE<SegmentError>>
pub fn solve_segment_id(
&self,
segment: impl ToSegmentId
) -> Result<SegmentId, PE<SegmentError>>
Resolves the segment to a SegmentId, considering the transaction
Example
let mut tx = persy.begin()?;
tx.create_segment("my_new_segment")?;
let segment_id = tx.solve_segment_id("my_new_segment")?;
Resolves the index name to a IndexId, considering the transaction, this has no public use as today, but may be used in future.
Example
let mut tx = persy.begin()?;
tx.create_index::<u8,u8>("my_new_index", ValueMode::Cluster)?;
let index_id = tx.solve_index_id("my_new_index")?;
pub fn insert(
&mut self,
segment: impl ToSegmentId,
rec: &[u8]
) -> Result<PersyId, PE<SegmentError>>
pub fn insert(
&mut self,
segment: impl ToSegmentId,
rec: &[u8]
) -> Result<PersyId, PE<SegmentError>>
Create a new record.
This function return an id that can be used by read
,
the record content can be read only with the transaction read
till the transaction is committed.
Example
let mut tx = persy.begin()?;
let data = vec![1;20];
tx.insert("seg", &data)?;
tx.prepare()?.commit()?;
Read the record content considering eventual in transaction changes.
Example
let mut tx = persy.begin()?;
let data = vec![1;20];
let id = tx.insert("seg", &data)?;
let read = tx.read("seg", &id)?.expect("record exists");
assert_eq!(data,read);
pub fn scan(
&mut self,
segment: impl ToSegmentId
) -> Result<TxSegmentIter<'_>, PE<SegmentError>>
pub fn scan(
&mut self,
segment: impl ToSegmentId
) -> Result<TxSegmentIter<'_>, PE<SegmentError>>
Scan for persistent and in transaction records
Example
let mut tx = persy.begin()?;
let data = vec![1;20];
let id = tx.insert("seg", &data)?;
let mut count = 0;
for (id,content) in tx.scan("seg")? {
println!("record size:{}",content.len());
count+=1;
}
assert_eq!(count,1);
Update the record content.
This updated content can be read only with the [transaction read
] till the transaction is committed.
Example
let mut tx = persy.begin()?;
let data = vec![1;20];
let id = tx.insert("seg", &data)?;
let new_data = vec![2;20];
tx.update("seg", &id, &new_data)?;
pub fn delete(
&mut self,
segment: impl ToSegmentId,
id: &PersyId
) -> Result<(), PE<DeleteError>>
pub fn delete(
&mut self,
segment: impl ToSegmentId,
id: &PersyId
) -> Result<(), PE<DeleteError>>
Delete a record.
The record will result deleted only reading it with transaction read
till the transaction is committed.
Example
let mut tx = persy.begin()?;
let data = vec![1;20];
let id = tx.insert("seg", &data)?;
tx.delete("seg", &id)?;
pub fn create_index<K, V>(
&mut self,
index_name: &str,
value_mode: ValueMode
) -> Result<(), PE<CreateIndexError>> where
K: IndexType,
V: IndexType,
pub fn create_index<K, V>(
&mut self,
index_name: &str,
value_mode: ValueMode
) -> Result<(), PE<CreateIndexError>> where
K: IndexType,
V: IndexType,
Create a new index with the name and the value management mode.
The create operation require two template arguments that are the types as keys and values of the index this have to match the following operation on the indexes.
Example
let mut tx = persy.begin()?;
tx.create_index::<u8,u8>("my_new_index", ValueMode::Cluster)?;
Check if a segment already exist in the storage considering the transaction
Example
let mut tx = persy.begin()?;
tx.create_index::<u8,u8>("my_new_index", ValueMode::Replace)?;
assert!(tx.exists_index("my_new_index")?);
Put a key value in an index following the value mode strategy.
Example
let mut tx = persy.begin()?;
tx.create_index::<u8,u8>("my_new_index", ValueMode::Cluster)?;
tx.put::<u8,u8>("my_new_index",10,10)?;
tx.prepare()?.commit()?;
Remove a key and optionally a specific value from an index following the value mode strategy.
Example
let mut tx = persy.begin()?;
tx.create_index::<u8,u8>("my_new_index", ValueMode::Cluster)?;
tx.put::<u8,u8>("my_new_index",10,10)?;
tx.remove::<u8,u8>("my_new_index",10,Some(10))?;
Get a value or a group of values from a key considering changes in transaction.
Example
tx.put::<u8,u8>("my_new_index",10,10)?;
let values = tx.get::<u8,u8>("my_new_index",&10)?;
for value in values {
//...
}
Get one value or none from a key considering changes in transaction.
Example
tx.put::<u8,u8>("my_new_index",10,10)?;
if let Some(value) = tx.one::<u8,u8>("my_new_index",&10)?{
//...
}
pub fn range<'a, K, V, R>(
&'a mut self,
index_name: &str,
range: R
) -> Result<TxIndexIter<'a, K, V>, PE<IndexOpsError>> where
K: IndexType,
V: IndexType,
R: RangeBounds<K>,
pub fn range<'a, K, V, R>(
&'a mut self,
index_name: &str,
range: R
) -> Result<TxIndexIter<'a, K, V>, PE<IndexOpsError>> where
K: IndexType,
V: IndexType,
R: RangeBounds<K>,
Browse a range of keys and values from an index including the transaction changes
Example
let mut tx = persy.begin()?;
tx.put::<u8,u8>("my_new_index",10,10)?;
{
let iter:TxIndexIter<u8,u8> = tx.range("my_new_index",10..12)?;
for (k,values) in iter {
for value in values {
//...
}
}
}
tx.prepare()?.commit()?;
Rollback a not yet prepared transaction.
All the resources used for eventual insert or update are released.
Example
let mut tx = persy.begin()?;
let data = vec![1;20];
tx.insert("seg", &data)?;
tx.rollback()?;
Prepare to commit a transaction, when this method return all the validation checks are done and is guaranteed that the transaction can be committed successfully
it will lock all the records involved in the transaction
till a commit
or rollback
is called.
Example
let mut tx = persy.begin()?;
//Do what ever operations on the records
let data = vec![1;20];
tx.insert("seg", &data)?;
tx.prepare()?;
List all the existing segments, considering all the changes in transaction.
Example
let mut tx = persy.begin()?;
tx.create_segment("seg")?;
let segments = tx.list_segments()?;
let names = segments.into_iter().map(|(name,_id)|name).collect::<Vec<String>>();
assert!(names.contains(&"seg".to_string()));
tx.prepare()?.commit()?;
List all the existing indexes, considering changes in the transaction.
Example
let mut tx = persy.begin()?;
tx.create_index::<u8, u8>("idx", ValueMode::Replace)?;
let indexes = tx.list_indexes()?;
let names = indexes.into_iter().map(|(name,_id)|name).collect::<Vec<String>>();
assert!(names.contains(&"idx".to_string()));
tx.prepare()?.commit()?;