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As your application evolves, you will often need to alter a table’s schema — adding columns to store new data, changing a column’s type or constraints, or removing columns that are no longer needed. MySQL UI handles all of these operations from the Structure tab without requiring you to write ALTER TABLE statements manually. To get started, select a table from the sidebar and click the Structure tab.

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Adding a column

  1. Click Add Column at the top-right of the columns section. The Add column dialog opens.
  2. Fill in the column details:
    • Column name — the name for the new column.
    • Type — choose a data type from the dropdown (e.g., INT, VARCHAR(255), TEXT, DATETIME, BOOLEAN, JSON). If the type you need is not in the list, type it directly into the custom type field below the dropdown.
    • Nullable — select NULL (nullable) to allow null values, or NOT NULL to require a value on every row.
    • Default value — optionally enter a default that MySQL will use when no value is supplied. Leave this empty for no default.
  3. Click Add Column to confirm. The new column is appended to the table and the column list refreshes.

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Modifying a column

  1. Find the column you want to change in the columns table.
  2. Click the pencil icon on that row. The Modify column dialog opens, pre-filled with the column’s current definition.
  3. Update any combination of the following:
    • Column name — rename the column.
    • Type — change the data type. Type the new type directly into the field (e.g., VARCHAR(500), BIGINT).
    • Nullable — switch between NULL (nullable) and NOT NULL.
    • Default value — set, change, or clear the default.
  4. Click Save Changes. MySQL UI runs ALTER TABLE ... MODIFY COLUMN and the column list updates to reflect the change.
Be careful when modifying columns that other tables reference through foreign keys. Changing the type of a referenced column — for example, from INT to BIGINT — may require updating the referencing columns in those other tables as well, or MySQL will reject the change.

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Dropping a column

  1. Find the column you want to remove in the columns table.
  2. Click the trash icon on that row.
  3. A confirmation dialog appears describing the column that will be dropped.
  4. Click Drop Column to confirm.
Dropping a column permanently deletes all data stored in that column for every row in the table. This action cannot be undone. Export your data before dropping a column if there is any chance you will need it later.