nextval ALTER TABLE t1 ALTER c4 SET DATA TYPE VARCHAR ( 50 ), COLUMN c4 DROP DEFAULT ALTER TABLE t1 ALTER c5 COMMENT '50 character column' DESC TABLE t1 + -+-+-+-+-+-+-+-+-+-+ | name | type | kind | null? | default | primary key | unique key | check | expression | comment | |-+-+-+-+-+-+-+-+-+-| | C1 | NUMBER(38,0) | COLUMN | Y | NULL | N | N | NULL | NULL | NULL | | C2 | NUMBER(38,0) | COLUMN | Y | NULL | N | N | NULL | NULL | NULL | | C3 | NUMBER(38,0) | COLUMN | Y | 5. nextval, c4 VARCHAR ( 20 ) DEFAULT 'abcde', c5 STRING ) DESC TABLE t1 + -+-+-+-+-+-+-+-+-+-+ | name | type | kind | null? | default | primary key | unique key | check | expression | comment | |-+-+-+-+-+-+-+-+-+-| | C1 | NUMBER(38,0) | COLUMN | N | NULL | N | N | NULL | NULL | NULL | | C2 | NUMBER(38,0) | COLUMN | Y | 3 | N | N | NULL | NULL | NULL | | C3 | NUMBER(38,0) | COLUMN | Y | | N | N | NULL | NULL | NULL | | C4 | VARCHAR(20) | COLUMN | Y | 'abcde' | N | N | NULL | NULL | NULL | | C5 | VARCHAR(16777216) | COLUMN | Y | NULL | N | N | NULL | NULL | NULL | + -+-+-+-+-+-+-+-+-+-+ĪLTER TABLE t1 ALTER COLUMN c1 DROP NOT NULL ALTER TABLE t1 MODIFY c2 DROP DEFAULT, c3 SET DEFAULT seq5. Regarding metadata (for example, the COMMENT field):ĬREATE OR REPLACE TABLE t1 ( c1 NUMBER NOT NULL, c2 NUMBER DEFAULT 3, c3 NUMBER DEFAULT seq1. ![]() Simulate a query on the column(s) protected by a masking policy. ![]() When modifying one or more table columns with a masking policy, use the POLICY_CONTEXT function to Matches the columns specified in the policy. If the precision of a column is decreased below the maximum precision of any column data retained in Time Travel, you cannot restore the table without first increasing the precision.Ī single masking policy that uses conditional columns can be applied to multiple tables provided that the column structure of the table Related Articles PostgreSQL rename attribute in jsonb field Postgresql query array of objects in JSONB field Postgresql query for objects in nested JSONB. Increase the precision of the specified number column.ĭecrease the precision of the specified number column if the new precision is sufficient to holdįor text data types, TYPE can be used only to increase the length of the column. type) must beįor the NUMBER data type, TYPE can be used to: When setting the TYPE for a column, the specified type (i.e. The default value for rows inserted after the column was added.ĭropping the default column value from any clone of the table is also prohibited. If the default were dropped, then the column would contain:Ī NULL value for rows inserted before the column was added. Rows inserted after the column was added. This restriction prevents inconsistency between values in rows inserted before the column was added and ĬREATE TABLE t ( x INT ) INSERT INTO t VALUES ( 1 ), ( 2 ), ( 3 ) ALTER TABLE t ADD COLUMN y INT DEFAULT 100 INSERT INTO t ( x ) VALUES ( 4 ), ( 5 ), ( 6 ) ALTER TABLE t ALTER COLUMN y DROP DEFAULT
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