Columns Count

The statistics show the evolution of the database with respect to the number of columns; the value is computed as the sum, over all the tables, of the columns'number per table. The revision's number in x-axis of the line chart, is an identification number in place of the real revision's number, which can be found in the attached csv file

SELECT d.svn_version, count(*) FROM PRISM_COLUMNS c,PRISM_VERSIONS d WHERE c.table_schema = d.schema_unique_name AND c.table_schema like ? GROUP BY d.svn_version ORDER BY d.tstart

Columns Lifetime

The statistics show the lifetimes of each column: the life of the columns is the number of revision where it is present; it doesn't necessary mean the column was live for consecutive revisions, this is just a qualitative chart to represent the number of revision where column was present

SELECT COLUMN_NAME, COUNT(*) FROM PRISM_COLUMNS WHERE TABLE_SCHEMA LIKE ? GROUP BY TABLE_NAME,COLUMN_NAME ORDER BY count(*) DESC