10/3/2023 0 Comments Postgresql alter table onlyThe ALTER TABLE in the output is the response that we receive. On the first line above we run our SQL statement. Let's rename our users table to all_users. We then need to specify what we want to rename the table to using the TO clause followed by the new name. A table can be renamed using the RENAME clause. One example of a change we might want to make to a table is to rename the table itself. "users_id_key" UNIQUE CONSTRAINT, btree (id) Id | integer | not null default nextval('users_id_seq'::regclass) Remember that within the psql console we can use the meta-command \d followed by a table name to describe that table. In a moment we'll work through some specific examples of using the ALTER TABLE statement, but first let's remind ourselves of what our table currently looks like. The basic format of an ALTER TABLE statement is: ALTER TABLE table_to_change An ALTER TABLE statement is part of DDL, and is for altering a table schema only we'll look at updating data in a table later in this book. Alter Table SyntaxĮxisting tables can be altered with an ALTER TABLE statement. Before jumping in to alter your table, take extra time to think about how the change will affect your existing data. Deleting a column means all data in that column will be lost forever. Adding an extra column to a table will add an extra column to all existing rows, just as it would in a spreadsheet. It is important to consider how schema changes will affect the data in a table.
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