Sometimes alter table commands create problems in the SQLite as follows. They run as fast on a table with 10 million columns as on a table with 1 row. Along these lines, the execution season of such ALTER TABLE commands is free of the measure of information in the table. No progressions are made to table substance for renames or column expansion. We can use SQL text with the ALTER TABLE command by adjusting the mapping in the sqlite_schema table. Future adaptations of SQLite may change to approve CHECK constraints as they are added. This can bring about a table that contains information that is infringing upon the CHECK constraint. Note likewise that while adding a CHECK constraint, the CHECK constraint isn’t tried against previous rows of the table. The column may not be GENERATED ALWAYS … Put away, however, VIRTUAL columns are permitted.In the event that foreign key imperatives are empowered and a column with a REFERENCES clause is added, the column should have a default estimation of NULL.On the off chance that a NOT NULL limitation is determined, the column should have default value other than NULL.The new column might not have a default estimation of CURRENT_TIME, CURRENT_DATE, CURRENT_TIMESTAMP, or an expression in brackets. The new column might not have a PRIMARY KEY or UNIQUE requirement.The new column may take any of the structures passable in a CREATE TABLE statement, with the accompanying limitations: The new column rule characterizes the qualities of the new segment. The new column is constantly added to the furthest limit of the rundown of existing columns. The ADD COLUMN syntax is utilized to add another new column into the current table.
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