Release 0.3 - Tables

This release adds the following functionality:

• Relational Tables on a Spreadsheet
  We now support relational tables on a spreadsheet. We do not maintain a copy of the tables on the spreadsheet; thus the underlying database has the only copy of the table. Any updates to the tabular regions on the sheet are pushed in real-time to the database. We support the following operations:
  • Link Table: Declare an area on the spreadsheet linked with a relational table in the database.
  • Create Table: Create a relational table based on a region on the sheet and link the region to the newly created table.
  • Add/Delete Columns: Append columns to a linked table or delete existing columns.
  • Add/Delete Rows: Append rows to a linked table or delete existing columns.
• R-tree for dependency
  The dependency table in internally handled by using an R-tree to improve scalability.
• Relational Operators
  We now support the following set/relational-operator-like operations within formulae:
  UNION,
  DIFFERENCE,
  INTERSECTION,
  CROSSPRODUCT,
  PROJECT,
  RENAME
• SQL Function
  We allow users to execute arbitrary SQL statements using a new function SQL.
• Multi-cell functions
  The relational operators are multi-cell functions, i.e., the output can consist of a collection of cells.
• Asynchronous formula computation
  The formulae on the spreadsheet will be computed asynchronously thereby not blocking the users.
• Private sheets
  We now support user login and have individual books for the users.

Known Issues

• New records can be only added to the bottom of the table.
• The only way to reorder tuples is to delete and add new at the bottom.
• The updates from the backend database are not pushed to the front end in real time. Refreshing a spreadsheet will reload the updates from the database.
• Database errors cascade across other operations.