Struct persy::Transaction

source · [−]
pub struct Transaction { /* private fields */ }
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")?);

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")?;

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);

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)?;

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)?;

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)?;

Drop an existing index.

Example
let mut tx = persy.begin()?;
tx.drop_index("my_new_index")?;

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)?{
 //...
}

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()?;

Prepare and Commit a transaction

Example
let mut tx = persy.begin()?;
//Do what ever operations on the records
let data = vec![1;20];
tx.insert("seg", &data)?;
tx.commit()?;

Trait Implementations

Executes the destructor for this type. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.