How to transform table with postgresql?

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by brandy , in category: MySQL , a month ago

How to transform table with postgresql?

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1 answer

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by jerad , a month ago

@brandy 

To transform a table with PostgreSQL, you can use the ALTER TABLE statement. Here are some common transformations you can make to a table:

  1. Add a new column:
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ALTER TABLE table_name
ADD column_name data_type;


  1. Remove a column:
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ALTER TABLE table_name
DROP COLUMN column_name;


  1. Rename a column:
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ALTER TABLE table_name
RENAME COLUMN old_column_name TO new_column_name;


  1. Change the data type of a column:
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ALTER TABLE table_name
ALTER COLUMN column_name TYPE new_data_type;


  1. Rename a table:
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ALTER TABLE old_table_name
RENAME TO new_table_name;


  1. Add a primary key constraint:
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ALTER TABLE table_name
ADD PRIMARY KEY (column_name);


  1. Add a foreign key constraint:
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ALTER TABLE table_name
ADD CONSTRAINT fk_constraint_name
FOREIGN KEY (column_name) REFERENCES other_table_name (other_column_name);


These are just a few examples of the transformations you can make to a table in PostgreSQL. Make sure to carefully review the PostgreSQL documentation for more information on the various transformations available.