ALTERTABLEtab_nameALTERCOLUMNcol_1TYPEnew_data_type,ALTERCOLUMNcol_2TYPEnew_data_type; Example: How to update data types of several columns using a single command in PostgreSQL? From the snippet shown in step 4 of the previous example, we can observe that the“team_rating”and“team_lead”...
How to Use RENAME COLUMN Command to Rename Columns in PostgreSQL? The“RENAME COLUMN”command can also be used as“RENAME”. TheRENAME COLUMNcommand gets executed with the assistance ofALTER TABLEcommand, as shown in the following syntax: ALTERTABLEtab_nameRENAMECOLUMNold_col_nameTOnew_col_name;...
Example: You have a table with a large column of data not accessed frequently, and you want to compress it to save disk space; this strategy will compress it but will avoid storing it out of line. Navigating the pitfalls of using TOAST in PostgreSQL While the TOAST technique can be ...
How to Drop the Column’s Default Value Using ALTER TABLE Statement? If you no longer want to set a default value for a column, then you can use the ALTER TABLE statement to drop the default value: ALTER TABLE table_name ALTER COLUMN column_name DROP DEFAULT; Example: Dropping a Default...
After that, we have to execute the ADD COLUMN command in order to add a new column to the table as seen here: ALTERTABLEtable_nameADDCOLUMNnew_column data_type;Copy Code Next, we can verify if the new column has been added by right-clicking the table name and selecting the Refresh opt...
PostgreSQL throws an error if you try to rename the non-existing table. In order to avoid this situation, you need to add the IF EXISTS parameter as follows: Code: ALTER TABLE IF EXISTS table_name RENAME TO new_table_name; In order to rename multiple tables at a time, you need to ex...
How to Use string_agg() Database Management How to Create a Table How to Drop a Table How to Rename a Table How to Truncate a Table How to Duplicate a Table How to Add a Column How to Change a Column Name How to Add a Default Value How to Remove a Default Value From a Column ...
On the other hand, “mentor_role” can be displayed as the altered role that is located in the column of “Role name”. Protect Role by ALTER ROLE in PostgreSQL PostgreSQL provides the facility to protect the specified role in the database. For this, the “ALTER ROLE” statement is utili...
Option #2: Execute this query to forcefully terminate the backend process: Copy 1SELECTpg_terminate_backend(<pid of the process>); How to rename a database in PostgreSQL? To rename a database in PostgreSQL, you can use theALTER DATABASEstatement followed by theRENAME TOclause. For example,...
How to Change Table Data in PostgreSQL We can change the definition of our tables with the following general syntax: ALTER TABLE table_nameAction_TO_Take; For example, we can add a column to our "pg_equipment" table by entering this command: ...