Programming Concepts

These concepts and definitions pave the way to a more detailed understanding of applications programming with ActiveSpaces software.

Data Grid
A distributed database, including all the component processes that implement it.
Connection
An application program connects to a data grid. A connection object is analogous to a traditional database connection.
Session
An application program interacts with a data grid through one or more session objects. Each session insulates the data grid interactions within one program thread from the interactions in other threads.

A session can be transacted or non-transacted. Get, put, and delete operations in a transacted session occur within a transaction, and do not take effect until the program explicitly commits the transaction.

Table
An ActiveSpaces data grid organizes and presents data as rows in tables, like a traditional relational database.

Administrators define tables within the data grid.

Programs can get a row from a table, put a row into a table, and delete a row from a table.

Programs can query a table for the rows that match a filter.

Primary Key

Each table distinguishes a primary key, or more briefly, the key.

Values of the key are unique: no two rows in a table have the same key value.

Secondary Index

A table can have zero or more secondary indexes, which facilitate queries. The tibdg tool can be used to create a secondary index on a table by using the index create command.

Iterator

An iterator presents an application program with the results of a data grid query, one row at a time.

  • Structuring Programs
    These steps outline the main structural components of most application programs that access a ActiveSpaces data grid.
  • Querying a Data Grid Table
    Application programs have the following options to query tables in a data grid.
  • Modifying Data in a Table
  • Transaction Isolation
    ActiveSpaces enforces the highest level of transaction isolation: serializable. As a result, serialization can delay database operations as transactions wait for other transactions to commit or roll back.
  • Listeners
    Listeners are used to monitor events corresponding to changes in a table.