You can change the data type of any column if all rows of the column contain nulls. However, if you change the data type of a column in a materialized view container table, then Oracle Database invalidates the corresponding materialized view.
US Economy. Definition: A stock market crash is when stock indexes lose more than 10% in a day or two. The broad indexes are the Dow Jones Industrial Average, the S&P 500, and the NASDAQ. The rapidity of the decline differentiates it from a stock market correction. That's a 10% loss over days, weeks or even months.
US Economy. The stock market crash of 2008 occurred on September 29, 2008. The Dow Jones Industrial Average fell 777.68 points in intra-day trading. That was the largest point drop in any single day in history. It plummeted because Congress rejected the bank bailout bill.