The postgresql documentation for the alter table method does not tell me explicitly about this particular problem: ĭo I really need to use a prefix like ' backup' instead of '_' ? Or would it be possible to rename it, my only interest is to maintain the information in the table whilst having the minimal changes to the table name. I am using pgAdmin III to access the database tables and making use of it's 'rename' operation results in the same error. Example: RENAME EMPLOYEE1 TO EMPLOYEE2 Or. Syntax: ALTER tableName RENAME TO newTableName. The '_my_table' table is a fake name, but this error is reproduced by actually creating a '_my_table' table and running the same script above. We can also use the ALTER TABLE statement to change the table name. NOTICE: table "_my_table" does not exist, skipping ERROR:ĮRROR: type "_my_table" already exists SQL state: 42710 Use the ALTER TABLE RENAME TO statement to change name of the existing table. The result of the query is the following: But this is not working: DROP TABLE IF EXISTS _my_table - table does not exists, this does nothing ![]() For this I thought of renaming the older tables so they have an underscore as a prefix. The COLUMN keyword in the statement is optional therefore you can omit. If you remove a table that does not exist, PostgreSQL. Second, use the IF EXISTS option to remove the table only if it exists. To drop a table from the database, you use the DROP TABLE statement as follows: First, specify the name of the table that you want to drop after the DROP TABLE keywords. Third, specify the new name for the column after the TO keyword. To set a new default for a column, use a command like: ALTER TABLE products ALTER COLUMN price SET DEFAULT 7.77 Note that this doesn't affect any existing rows in the table, it just changes the default for future INSERT commands. Introduction to PostgreSQL DROP TABLE statement. Write a script to rename any single column within the created table. ![]() Create a Sample table with a few columns in PostgreSQL. Second, provide name of the column that you want to rename after the RENAME COLUMN keywords. Here Ill explain how you can rename the column only if the specified column exists in your PostgreSQL database table with a simple and issue example. The RENAME forms change the name of a table (or an index, sequence, or view) or the name of an individual column in a table. Now create a second table, and swap them.I have a database which relies on a PostgreSQL system and I am maintaining it so I want to change tables and overall scheme. First, specify the name of the table that contains the column which you want to rename after the ALTER TABLE clause. Now, you can rename the suppliergroups table to groups as follows. ![]() SELECT pg_get_viewdef('v_tmp_test_a'::regclass, false) The output shows that the suppliers table has a foreign key constraint which references the suppliergroups table. ![]() Now look at what the VIEW is using (now is using tmp_test_a, which is what it should be using): Here is a test case to illustrate what I mean: CREATE TABLE tmp_test_a (num integer) ĬREATE VIEW v_tmp_test_a AS SELECT * FROM tmp_test_a Next thing I know after I rename the table, the definition for foo has changed to point to table abc. So I rename the table with: ALTER TABLE xyz RENAME TO abc Īnd my VIEW defition for the sake of example is: CREATE VIEW foo AS SELECT * FROM xyz In the above syntax, tablename1 is the name of the table where you want to add a FOREIGN KEY. The syntax is as follow: ALTER TABLE tablename1 ADD FOREIGN KEY (columnname1) REFERENCES tablename2. I've found out today that renaming tables in Postgresql also renames the VIEW definitions for Views that use the table I renamed automatically? Is there any way to turn this off? You can add FOREIGN KEY to the table in PostgreSQL, by using the ALTER TABLE ADD FOREIGN KEY statement.
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