Oracle (3) Database

Lock:

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2. Row-Level Lock

SELECT... For update Syntax:

Wait

3. Table-Level Lock:

(1) shared lock:

(2) exclusive lock:

(3) deadlock

4. Table Partitioning

(1) range partitioning

Insert (partition in two ranges)

(2) hash partitions

(3) List partition (allow users to organize irrelevant data together)

(4) composite Partition

(5) query the field tablespace (users is used by default to view the partition)

(6) add partitions

1. Last insert

Alter table sales (table Name) add partition p3 values less than (maxvalues );

2. insert it into a shard in the middle (split p3 into two shards)

Alter table sales

Split partition p3 at (2000)

Into (partition p21. partition p22 );

(7) delete partitions

Alter table sales drop partition p2;

(8) Partition truncation (delete all records in a specified partition)

Alter table sales truncate partition p2;

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5. View All Tables and fields in Oracle

Get table:

Select table_name from user_tables; // The table of the current user

Select table_name from all_tables; // tables of all users

Select table_name from dba_tables; // includes the system table

Select table_name from dba_tables where owner = "username'

6. Create a common permission

Authorization:

Create Synonym

(1) Private (common)

(2) Public

Create or replace an existing Synonym

Delete Synonym

Drop synonym emp;

Drop public synonym emp;

7. Sequence

NEXTVAL returns the next value of the sequence

CURRVAL returns the current value of the sequence

8. Create an attempt

9. Modify the view by ing the table

10. delete a view

11. Violation

12. The view cannot be changed.

13. display time

14. Create an index

Due to the long time:

Index: (improves query speed (performance ))

Step 1: Sort

.