Two-phase commit is mechanism that guarantees a distributed transaction EIther commits on all involved nodes or rolls back on all involved nodes to maintain data consistency across the GLobal distributed database. It has two phase, a prepare phase and a commit...
Two phase commit is applicable in a Distributed or In-Doubt Transactions. The two-phase commit mechanism is applicable in a Distributed or In-Doubt Transactions. If the Distributed transaction fai...
How to design the inter - connection network for parallel processing
.1. How pipeline promotes parallel processing?Explain with examples.2. Mention the hardware issues involved in parallel processing? 3.Give the purpose of having buses in distrubuted parallel processing?
What are web database?Advantages and application of web database.
130. What is distributed database ?
A distributed database is a network of databases managed by multiple database servers that appears to a user as single logical database. The data of all databases in the distributed database can be simultaneously...
Describe two phases of two-phase commit ?
Prepare phase - the GLobal coordinator (initiating node) ask a participants to prepare (to promise to commit or rollback the transaction, even if there is a failure) commit - phase - if all participants respond to the coordinator that they are ...
What is the mechanism provided by Oracle for table replication ?
Snapshots and snapshot logs
Snapshots are read-only copies of a master table located on a remote node which is periodically refreshed to reflect changes made to the master table.
A snapshot log is a table in the master database that is associated with the master table. Oracle uses a snapshot log to track the rows that have been updated in the master table. Snapshot logs are used in updating the snapshots based on the master...
SQL *net is Oracle's mechanism for interfacing with the communication protocols used by the networks that facilitate distributed processing and distributed databases. it is used in clint-server and server-server...
What are the various type of snapshots?
simple and complex.
How can we reduce the network traffic?
- replication of data in distributed environment. - using snapshots to replicate data. - using remote procedure calls.
snapshot is an object used to dynamically replicate data between distribute database at specified time intervals. In ver 7.0 they are read only.
Differentiate simple and complex, snapshots ?
- a simple snapshot is based on a query that does not contains group by clauses, connect by clauses, joins, sub-query or snashot of operations. - a complex snapshots contain atleast any one of the above.
What dynamic data replication?
updating or inserting records in remote database through database triggers. It may fail if remote database is having any problem.
How can you enforce referential integrity in snapshots ?
time the references to occur when master tables are not in use. peform the reference the manually immdiately locking the master tables. We can join tables in snopshots by creating a complex snapshots that will based on the master tables.
what are the options available to refresh snapshots ?
complete - tables are completely regenerated using the snapshots query and the master tables every time the snapshot referenced.Fast - if simple snapshot used then a snapshot log can be used to send the changes to the snapshot tables.Force - ...
it is a table that maintains a record of modifications to the master table in a snapshot. it is stored in the same database as master table and is only available for simple snapshots. it should be created before creating snapshots.
When will the data in the snapshot log be used?
we must be able to create a after row trigger on table (i.E., it should be not be already available) after giving table privileges. we cannot specify snapshot log name because Oracle uses the name of the master table in the name of the database objects that support its snapshot log. the...
What are the benefits of distributed options in databases?
database on other servers can be updated and those transactions can be grouped together with others in a logical unit.Database uses a two phase commit.
you can convert the access file to csv then import it via sql loader. If you need any further help let me know, i will give you the script for loading data.