oracle:sql:delete_drop_or_truncate
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| oracle:sql:delete_drop_or_truncate [2021/08/08 16:44] – peter | oracle:sql:delete_drop_or_truncate [2021/08/08 17:53] (current) – peter | ||
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| ====== Oracle - SQL - Delete, Drop, or Truncate ====== | ====== Oracle - SQL - Delete, Drop, or Truncate ====== | ||
| - | |DELETE|The DELETE command is used to remove rows from a table.| | + | |**DELETE**|The DELETE command is used to remove rows from a table.| |
| |:::|A WHERE clause can be used to only remove some rows.| | |:::|A WHERE clause can be used to only remove some rows.| | ||
| |:::|If no WHERE condition is specified, all rows will be removed.| | |:::|If no WHERE condition is specified, all rows will be removed.| | ||
| |:::|After performing a DELETE operation you need to COMMIT or ROLLBACK the transaction to make the change permanent or to undo it.| | |:::|After performing a DELETE operation you need to COMMIT or ROLLBACK the transaction to make the change permanent or to undo it.| | ||
| |:::|Note that this operation will cause all DELETE triggers on the table to fire.| | |:::|Note that this operation will cause all DELETE triggers on the table to fire.| | ||
| - | |DROP|The DROP command removes a table from the database.| | + | |**DROP**|The DROP command removes a table from the database.| |
| |:::|All the tables' | |:::|All the tables' | ||
| |:::|No DML triggers will be fired.| | |:::|No DML triggers will be fired.| | ||
| |:::|The operation cannot be rolled back.| | |:::|The operation cannot be rolled back.| | ||
| - | |TRUNCATE|TRUNCATE removes all rows from a table.| | + | |**TRUNCATE**|TRUNCATE removes all rows from a table.| |
| |:::|The operation cannot be rolled back and no triggers will be fired.| | |:::|The operation cannot be rolled back and no triggers will be fired.| | ||
| |::: | |::: | ||
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| * Truncate resets identity of table. | * Truncate resets identity of table. | ||
| * It locks the entire table. | * It locks the entire table. | ||
| - | * It is DDL(Data Definition Language). | + | * It is DDL (Data Definition Language). |
| * The WHERE clause cannot be used with it. | * The WHERE clause cannot be used with it. | ||
| * Trigger is not fired while truncate. | * Trigger is not fired while truncate. | ||
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| </ | </ | ||
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| + | **DELETE with WHERE** | ||
| <code sql> | <code sql> | ||
oracle/sql/delete_drop_or_truncate.1628441073.txt.gz · Last modified: 2021/08/08 16:44 by peter