Increase the rules of columns to a table
You can not be specified as a column of not null at any time.
How to add a NOT NULL column?
Press the steps:
1, increasing columns but not set to not null.
2, add this column to each line.
3. Modify this column to Not NULL.
Modify the rules of the column:
Can increase the width of the characteristic column at any time
You can increase the number of bits of Number type columns at any time.
You can increase or reduce the number of decimal points of Number type column at any time.
When the table is empty
Can change data type
Can reduce the width of the characteristic column
You can less Number rankings.
Or re-create after deleting the table.
