Initial commit
This commit is contained in:
Zhongwei Li
@@ -0,0 +1,861 @@
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---
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slug: /basic-sql-operations
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---
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# Basic SQL operations
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This topic introduces some basic SQL operations in seekdb.
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## Create a database
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Use the `CREATE DATABASE` statement to create a database.
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Example: Create a database named `db1`, specify the character set as `utf8mb4`, and set the read-write attribute.
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```sql
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obclient> CREATE DATABASE db1 DEFAULT CHARACTER SET utf8mb4 READ WRITE;
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Query OK, 1 row affected
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```
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For more information about the `CREATE DATABASE` statement, see [CREATE DATABASE](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974111).
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After creation, you can use the `SHOW DATABASES` command to view all databases in the current database server.
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```sql
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obclient> SHOW DATABASES;
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+--------------------+
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| Database |
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+--------------------+
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| db1 |
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| information_schema |
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| mysql |
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| oceanbase |
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| sys_external_tbs |
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| test |
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+--------------------+
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6 rows in set
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```
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## Table operations
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In seekdb, a table is the most basic data storage unit that contains all data accessible to users. Each table contains multiple rows of records, and each record consists of multiple columns. This topic provides the syntax and examples for creating, viewing, modifying, and deleting tables in a database.
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### Create a table
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Use the `CREATE TABLE` statement to create a new table in a database.
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Example: Create a table named `test` in the database `db1`.
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```sql
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obclient> USE db1;
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Database changed
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obclient> CREATE TABLE test (c1 INT PRIMARY KEY, c2 VARCHAR(3));
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Query OK, 0 rows affected
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```
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For more information about the `CREATE TABLE` statement, see [CREATE TABLE](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974140).
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### View tables
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Use the `SHOW CREATE TABLE` statement to view the table creation statement.
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Examples:
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* View the table creation statement for the table `test`.
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```sql
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obclient> SHOW CREATE TABLE test\G
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*************************** 1. row ***************************
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Table: test
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Create Table: CREATE TABLE `test` (
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`c1` int(11) NOT NULL,
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`c2` varchar(3) DEFAULT NULL,
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PRIMARY KEY (`c1`)
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) ORGANIZATION INDEX DEFAULT CHARSET = utf8mb4 ROW_FORMAT = DYNAMIC COMPRESSION = 'zstd_1.3.8' REPLICA_NUM = 1 BLOCK_SIZE = 16384 USE_BLOOM_FILTER = FALSE ENABLE_MACRO_BLOCK_BLOOM_FILTER = FALSE TABLET_SIZE = 134217728 PCTFREE = 0
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1 row in set
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```
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* Use the `SHOW TABLES` statement to view all tables in the database `db1`.
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```sql
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obclient> SHOW TABLES FROM db1;
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+---------------+
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| Tables_in_db1 |
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+---------------+
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| test |
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+---------------+
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1 row in set
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```
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### Modify a table
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Use the `ALTER TABLE` statement to modify the structure of an existing table, including modifying table attributes, adding columns, modifying columns and their attributes, and deleting columns.
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Examples:
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* Rename the column `c2` to `c3` in the table `test` and change its data type.
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```sql
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obclient> DESCRIBE test;
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+-------+------------+------+-----+---------+-------+
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| Field | Type | Null | Key | Default | Extra |
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+-------+------------+------+-----+---------+-------+
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| c1 | int(11) | NO | PRI | NULL | |
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| c2 | varchar(3) | YES | | NULL | |
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+-------+------------+------+-----+---------+-------+
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2 rows in set
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obclient> ALTER TABLE test CHANGE COLUMN c2 c3 CHAR(10);
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Query OK, 0 rows affected
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obclient> DESCRIBE test;
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+-------+----------+------+-----+---------+-------+
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| Field | Type | Null | Key | Default | Extra |
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+-------+----------+------+-----+---------+-------+
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| c1 | int(11) | NO | PRI | NULL | |
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| c3 | char(10) | YES | | NULL | |
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+-------+----------+------+-----+---------+-------+
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2 rows in set
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```
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* Add and delete columns in the table `test`.
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```sql
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obclient> DESCRIBE test;
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+-------+----------+------+-----+---------+-------+
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| Field | Type | Null | Key | Default | Extra |
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+-------+----------+------+-----+---------+-------+
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| c1 | int(11) | NO | PRI | NULL | |
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| c3 | char(10) | YES | | NULL | |
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+-------+----------+------+-----+---------+-------+
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2 rows in set
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obclient> ALTER TABLE test ADD c4 int;
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Query OK, 0 rows affected
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obclient> DESCRIBE test;
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+-------+----------+------+-----+---------+-------+
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| Field | Type | Null | Key | Default | Extra |
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+-------+----------+------+-----+---------+-------+
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| c1 | int(11) | NO | PRI | NULL | |
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| c3 | char(10) | YES | | NULL | |
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| c4 | int(11) | YES | | NULL | |
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+-------+----------+------+-----+---------+-------+
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3 rows in set
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obclient> ALTER TABLE test DROP c3;
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Query OK, 0 rows affected
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obclient> DESCRIBE test;
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+-------+---------+------+-----+---------+-------+
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| Field | Type | Null | Key | Default | Extra |
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+-------+---------+------+-----+---------+-------+
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| c1 | int(11) | NO | PRI | NULL | |
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| c4 | int(11) | YES | | NULL | |
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+-------+---------+------+-----+---------+-------+
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2 rows in set
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```
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For more information about the `ALTER TABLE` statement, see [ALTER TABLE](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974126).
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### Delete a table
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Use the `DROP TABLE` statement to delete a table.
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Example: Delete the table `test`.
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```sql
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obclient> DROP TABLE test;
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Query OK, 0 rows affected
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```
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For more information about the `DROP TABLE` statement, see [DROP TABLE](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974139).
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## Index operations
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An index is a structure created on a table that sorts the values of one or more columns in the database table. Its main purpose is to improve query speed and reduce the performance overhead of the database system. This topic introduces the syntax and examples for creating, viewing, and deleting indexes in a database.
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### Create an index
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Use the `CREATE INDEX` statement to create an index on a table.
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Example: Create an index on the table `test`.
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```sql
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obclient> CREATE TABLE test (c1 INT PRIMARY KEY, c2 VARCHAR(3));
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Query OK, 0 rows affected (0.10 sec)
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obclient> DESCRIBE test;
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+-------+------------+------+-----+---------+-------+
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| Field | Type | Null | Key | Default | Extra |
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+-------+------------+------+-----+---------+-------+
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| c1 | int(11) | NO | PRI | NULL | |
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| c2 | varchar(3) | YES | | NULL | |
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+-------+------------+------+-----+---------+-------+
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2 rows in set
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obclient> CREATE INDEX test_index ON test (c1, c2);
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Query OK, 0 rows affected
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```
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For more information about the `CREATE INDEX` statement, see [CREATE INDEX](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974165).
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### View indexes
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Use the `SHOW INDEX` statement to view indexes on a table.
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Example: View index information for the table `test`.
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```sql
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obclient> SHOW INDEX FROM test\G
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*************************** 1. row ***************************
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Table: test
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Non_unique: 0
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Key_name: PRIMARY
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Seq_in_index: 1
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Column_name: c1
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Collation: A
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Cardinality: NULL
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Sub_part: NULL
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Packed: NULL
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Null:
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Index_type: BTREE
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Comment: available
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Index_comment:
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Visible: YES
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Expression: NULL
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*************************** 2. row ***************************
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Table: test
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Non_unique: 1
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Key_name: test_index
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Seq_in_index: 1
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Column_name: c1
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Collation: A
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Cardinality: NULL
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Sub_part: NULL
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Packed: NULL
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Null:
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Index_type: BTREE
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Comment: available
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Index_comment:
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Visible: YES
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Expression: NULL
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*************************** 3. row ***************************
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Table: test
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Non_unique: 1
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Key_name: test_index
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Seq_in_index: 2
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Column_name: c2
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Collation: A
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Cardinality: NULL
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Sub_part: NULL
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Packed: NULL
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Null: YES
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Index_type: BTREE
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Comment: available
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Index_comment:
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Visible: YES
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Expression: NULL
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3 rows in set
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```
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### Delete an index
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Use the `DROP INDEX` statement to delete an index on a table.
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Example: Delete the index on the table `test`.
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```sql
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obclient> DROP INDEX test_index ON test;
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Query OK, 0 rows affected
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```
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For more information about the `DROP INDEX` statement, see [DROP INDEX](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974168).
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## Insert data
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Use the `INSERT` statement to insert data into an existing table.
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Examples:
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* Create a table `t1` and insert one row of data.
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```sql
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obclient> CREATE TABLE t1(c1 INT PRIMARY KEY, c2 int) PARTITION BY KEY(c1) PARTITIONS 4;
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Query OK, 0 rows affected
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obclient> SELECT * FROM t1;
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Empty set
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obclient> INSERT t1 VALUES(1,1);
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Query OK, 1 row affected
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obclient> SELECT * FROM t1;
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+----+------+
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| c1 | c2 |
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+----+------+
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| 1 | 1 |
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+----+------+
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1 row in set
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```
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* Insert multiple rows of data into the table `t1`.
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```sql
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obclient> INSERT t1 VALUES(2,2),(3,default),(2+2,3*4);
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Query OK, 3 rows affected
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Records: 3 Duplicates: 0 Warnings: 0
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obclient> SELECT * FROM t1;
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+----+------+
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| c1 | c2 |
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+----+------+
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| 1 | 1 |
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| 2 | 2 |
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| 3 | NULL |
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| 4 | 12 |
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+----+------+
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4 rows in set
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```
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For more information about the `INSERT` statement, see [INSERT](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974718).
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## Delete data
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Use the `DELETE` statement to delete data. It supports deleting data from a single table or multiple tables.
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|
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Examples:
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|
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* Create tables `t2` and `t3` using `CREATE TABLE`. Delete the row where `c1=2`, where `c1` is the `PRIMARY KEY` column in the table `t2`.
|
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|
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```sql
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/*Table `t3` is a `KEY` partitioned table, and the partition names are automatically generated by the system according to the partition naming rules, that is, the partition names are `p0`, `p1`, `p2`, and `p3`*/
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obclient> CREATE TABLE t2(c1 INT PRIMARY KEY, c2 INT);
|
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Query OK, 0 rows affected
|
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obclient> INSERT t2 VALUES(1,1),(2,2),(3,3),(5,5);
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Query OK, 4 rows affected
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Records: 4 Duplicates: 0 Warnings: 0
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||||
|
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obclient> SELECT * FROM t2;
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+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 1 | 1 |
|
||||
| 2 | 2 |
|
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| 3 | 3 |
|
||||
| 5 | 5 |
|
||||
+----+------+
|
||||
4 rows in set
|
||||
|
||||
obclient> CREATE TABLE t3(c1 INT PRIMARY KEY, c2 INT) PARTITION BY KEY(c1) PARTITIONS 4;
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Query OK, 0 rows affected
|
||||
|
||||
obclient> INSERT INTO t3 VALUES(5,5),(1,1),(2,2),(3,3);
|
||||
Query OK, 4 rows affected
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||||
Records: 4 Duplicates: 0 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t3;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 5 | 5 |
|
||||
| 1 | 1 |
|
||||
| 2 | 2 |
|
||||
| 3 | 3 |
|
||||
+----+------+
|
||||
4 rows in set
|
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|
||||
obclient> DELETE FROM t2 WHERE c1 = 2;
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Query OK, 1 row affected
|
||||
|
||||
obclient> SELECT * FROM t2;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 1 | 1 |
|
||||
| 3 | 3 |
|
||||
| 5 | 5 |
|
||||
+----+------+
|
||||
3 rows in set
|
||||
```
|
||||
|
||||
* Delete the first row of data from the table `t2` after sorting by the `c2` column.
|
||||
|
||||
```sql
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||||
obclient> DELETE FROM t2 ORDER BY c2 LIMIT 1;
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Query OK, 1 row affected
|
||||
|
||||
obclient> SELECT * FROM t2;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 3 | 3 |
|
||||
| 5 | 5 |
|
||||
+----+------+
|
||||
2 rows in set
|
||||
```
|
||||
|
||||
* Delete data from the `p2` partition of the table `t3`.
|
||||
|
||||
```sql
|
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obclient> SELECT * FROM t3 PARTITION(p2);
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 1 | 1 |
|
||||
| 2 | 2 |
|
||||
| 3 | 3 |
|
||||
+----+------+
|
||||
3 rows in set
|
||||
|
||||
obclient> DELETE FROM t3 PARTITION(p2);
|
||||
Query OK, 3 rows affected
|
||||
|
||||
obclient> SELECT * FROM t3;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 5 | 5 |
|
||||
+----+------+
|
||||
1 row in set
|
||||
```
|
||||
|
||||
* Delete data from tables `t2` and `t3` where `t2.c1 = t3.c1`.
|
||||
|
||||
```sql
|
||||
obclient> SELECT * FROM t2;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 3 | 3 |
|
||||
| 5 | 5 |
|
||||
+----+------+
|
||||
2 rows in set
|
||||
|
||||
obclient> SELECT * FROM t3;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 5 | 5 |
|
||||
+----+------+
|
||||
|
||||
obclient> DELETE t2, t3 FROM t2, t3 WHERE t2.c1 = t3.c1;
|
||||
Query OK, 3 rows affected
|
||||
/*Equivalent to
|
||||
obclient> DELETE FROM t2, t3 USING t2, t3 WHERE t2.c1 = t3.c1;
|
||||
*/
|
||||
|
||||
obclient> SELECT * FROM t2;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 3 | 3 |
|
||||
+----+------+
|
||||
1 row in set
|
||||
|
||||
obclient> SELECT * FROM t3;
|
||||
Empty set
|
||||
```
|
||||
|
||||
For more information about the `DELETE` statement, see [DELETE](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974138).
|
||||
|
||||
## Update data
|
||||
|
||||
Use the `UPDATE` statement to modify field values in a table.
|
||||
|
||||
Examples:
|
||||
|
||||
* Create tables `t4` and `t5` using `CREATE TABLE`. Modify the `c2` column value to `100` for the row where `t4.c1=10` in the table `t4`.
|
||||
|
||||
```sql
|
||||
obclient> CREATE TABLE t4(c1 INT PRIMARY KEY, c2 INT);
|
||||
Query OK, 0 rows affected
|
||||
|
||||
obclient> INSERT t4 VALUES(10,10),(20,20),(30,30),(40,40);
|
||||
Query OK, 4 rows affected
|
||||
Records: 4 Duplicates: 0 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t4;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 10 | 10 |
|
||||
| 20 | 20 |
|
||||
| 30 | 30 |
|
||||
| 40 | 40 |
|
||||
+----+------+
|
||||
4 rows in set
|
||||
|
||||
obclient> CREATE TABLE t5(c1 INT PRIMARY KEY, c2 INT) PARTITION BY KEY(c1) PARTITIONS 4;
|
||||
Query OK, 0 rows affected
|
||||
|
||||
obclient> INSERT t5 VALUES(50,50),(10,10),(20,20),(30,30);
|
||||
Query OK, 4 rows affected
|
||||
Records: 4 Duplicates: 0 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t5;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 20 | 20 |
|
||||
| 10 | 10 |
|
||||
| 50 | 50 |
|
||||
| 30 | 30 |
|
||||
+----+------+
|
||||
4 rows in set
|
||||
|
||||
obclient> UPDATE t4 SET t4.c2 = 100 WHERE t4.c1 = 10;
|
||||
Query OK, 1 row affected
|
||||
Rows matched: 1 Changed: 1 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t4;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 10 | 100 |
|
||||
| 20 | 20 |
|
||||
| 30 | 30 |
|
||||
| 40 | 40 |
|
||||
+----+------+
|
||||
4 rows in set
|
||||
```
|
||||
|
||||
* Modify the `c2` column value to `100` for the first two rows of data in the table `t4` after sorting by the `c2` column.
|
||||
|
||||
```sql
|
||||
obclient> UPDATE t4 set t4.c2 = 100 ORDER BY c2 LIMIT 2;
|
||||
Query OK, 2 rows affected
|
||||
Rows matched: 2 Changed: 2 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t4;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 10 | 100 |
|
||||
| 20 | 100 |
|
||||
| 30 | 100 |
|
||||
| 40 | 40 |
|
||||
+----+------+
|
||||
4 rows in set
|
||||
```
|
||||
|
||||
* Modify the `c2` column value to `100` for the rows in the `p1` partition of the table `t5` where `t5.c1 > 20`.
|
||||
|
||||
```sql
|
||||
obclient> SELECT * FROM t5 PARTITION (p1);
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 10 | 10 |
|
||||
| 50 | 50 |
|
||||
+----+------+
|
||||
2 rows in set
|
||||
|
||||
obclient> UPDATE t5 PARTITION(p1) SET t5.c2 = 100 WHERE t5.c1 > 20;
|
||||
Query OK, 1 row affected
|
||||
Rows matched: 1 Changed: 1 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t5 PARTITION(p1);
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 10 | 10 |
|
||||
| 50 | 100 |
|
||||
+----+------+
|
||||
2 rows in set
|
||||
```
|
||||
|
||||
* For rows in tables `t4` and `t5` that satisfy `t4.c2 = t5.c2`, modify the `c2` column value in the table `t4` to `100` and the `c2` column value in the table `t5` to `200`.
|
||||
|
||||
```sql
|
||||
obclient> UPDATE t4,t5 SET t4.c2 = 100, t5.c2 = 200 WHERE t4.c2 = t5.c2;
|
||||
Query OK, 1 row affected
|
||||
Rows matched: 4 Changed: 1 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t4;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 10 | 100 |
|
||||
| 20 | 100 |
|
||||
| 30 | 100 |
|
||||
| 40 | 40 |
|
||||
+----+------+
|
||||
4 rows in set
|
||||
|
||||
obclient> SELECT * FROM t5;
|
||||
+----+------+
|
||||
| c1 | c2 |
|
||||
+----+------+
|
||||
| 20 | 20 |
|
||||
| 10 | 10 |
|
||||
| 50 | 200 |
|
||||
| 30 | 30 |
|
||||
+----+------+
|
||||
4 rows in set
|
||||
```
|
||||
|
||||
For more information about the `UPDATE` statement, see [UPDATE](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974152).
|
||||
|
||||
## Query data
|
||||
|
||||
Use the `SELECT` statement to query the contents of a table.
|
||||
|
||||
Examples:
|
||||
|
||||
* Create a table `t6` using `CREATE TABLE`. Read the `name` data from the table `t6`.
|
||||
|
||||
```sql
|
||||
obclient> CREATE TABLE t6 (id INT, name VARCHAR(50), num INT);
|
||||
Query OK, 0 rows affected
|
||||
|
||||
obclient> INSERT INTO t6 VALUES(1,'a',100),(2,'b',200),(3,'a',50);
|
||||
Query OK, 3 rows affected
|
||||
Records: 3 Duplicates: 0 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t6;
|
||||
+------+------+------+
|
||||
| ID | NAME | NUM |
|
||||
+------+------+------+
|
||||
| 1 | a | 100 |
|
||||
| 2 | b | 200 |
|
||||
| 3 | a | 50 |
|
||||
+------+------+------+
|
||||
3 rows in set
|
||||
|
||||
obclient> SELECT name FROM t6;
|
||||
+------+
|
||||
| NAME |
|
||||
+------+
|
||||
| a |
|
||||
| b |
|
||||
| a |
|
||||
+------+
|
||||
3 rows in set
|
||||
```
|
||||
|
||||
* Remove duplicates from the `name` column in the query results.
|
||||
|
||||
```sql
|
||||
obclient> SELECT DISTINCT name FROM t6;
|
||||
+------+
|
||||
| NAME |
|
||||
+------+
|
||||
| a |
|
||||
| b |
|
||||
+------+
|
||||
2 rows in set
|
||||
```
|
||||
|
||||
* Output the corresponding `id`, `name`, and `num` from the table `t6` based on the filter condition `name = 'a'`.
|
||||
|
||||
```sql
|
||||
obclient> SELECT id, name, num FROM t6 WHERE name = 'a';
|
||||
+------+------+------+
|
||||
| ID | NAME | NUM |
|
||||
+------+------+------+
|
||||
| 1 | a | 100 |
|
||||
| 3 | a | 50 |
|
||||
+------+------+------+
|
||||
2 rows in set
|
||||
```
|
||||
|
||||
For more information about the `SELECT` statement, see [SELECT](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974942).
|
||||
|
||||
## Commit a transaction
|
||||
|
||||
Use the `COMMIT` statement to commit a transaction.
|
||||
|
||||
Before committing a transaction (COMMIT):
|
||||
|
||||
* Your modifications are visible only to the current session and not visible to other database sessions.
|
||||
* Your modifications are not persisted. You can undo the modifications using the ROLLBACK statement.
|
||||
|
||||
After committing a transaction (COMMIT):
|
||||
|
||||
* Your modifications are visible to all database sessions.
|
||||
* Your modifications are successfully persisted and cannot be rolled back using the ROLLBACK statement.
|
||||
|
||||
Example: Create a table `t_insert` using `CREATE TABLE`. Use the `COMMIT` statement to commit the transaction.
|
||||
|
||||
```sql
|
||||
obclient> CREATE TABLE t_insert(
|
||||
id number NOT NULL PRIMARY KEY,
|
||||
name varchar(10) NOT NULL,
|
||||
value number,
|
||||
gmt_create DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
|
||||
);
|
||||
Query OK, 0 rows affected
|
||||
|
||||
obclient> BEGIN;
|
||||
Query OK, 0 rows affected
|
||||
|
||||
obclient> INSERT INTO t_insert(id, name, value, gmt_create) VALUES(1,'CN',10001, current_timestamp),(2,'US',10002, current_timestamp),(3,'EN',10003, current_timestamp);
|
||||
Query OK, 3 rows affected
|
||||
Records: 3 Duplicates: 0 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t_insert;
|
||||
+----+------+-------+---------------------+
|
||||
| id | name | value | gmt_create |
|
||||
+----+------+-------+---------------------+
|
||||
| 1 | CN | 10001 | 2025-11-07 16:01:53 |
|
||||
| 2 | US | 10002 | 2025-11-07 16:01:53 |
|
||||
| 3 | EN | 10003 | 2025-11-07 16:01:53 |
|
||||
+----+------+-------+---------------------+
|
||||
3 rows in set
|
||||
|
||||
obclient> INSERT INTO t_insert(id,name) VALUES(4,'JP');
|
||||
Query OK, 1 row affected
|
||||
|
||||
obclient> COMMIT;
|
||||
Query OK, 0 rows affected
|
||||
|
||||
obclient> exit;
|
||||
Bye
|
||||
|
||||
obclient> obclient -h127.0.0.1 -uroot -P2881 -Ddb1
|
||||
|
||||
obclient> SELECT * FROM t_insert;
|
||||
+------+------+-------+---------------------+
|
||||
| id | name | value | gmt_create |
|
||||
+------+------+-------+---------------------+
|
||||
| 1 | CN | 10001 | 2025-11-07 16:01:53 |
|
||||
| 2 | US | 10002 | 2025-11-07 16:01:53 |
|
||||
| 3 | EN | 10003 | 2025-11-07 16:01:53 |
|
||||
| 4 | JP | NULL | 2025-11-07 16:02:02 |
|
||||
+------+------+-------+---------------------+
|
||||
4 rows in set
|
||||
```
|
||||
|
||||
For more information about transaction control statements, see [Transaction management overview](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001971667).
|
||||
|
||||
## Roll back a transaction
|
||||
|
||||
Use the `ROLLBACK` statement to roll back a transaction.
|
||||
|
||||
Rolling back a transaction means undoing all modifications made in the transaction. You can roll back the entire uncommitted transaction or roll back to any savepoint in the transaction. To roll back to a savepoint, you must use the `ROLLBACK` statement together with `TO SAVEPOINT`.
|
||||
|
||||
* If you roll back the entire transaction:
|
||||
* The transaction ends.
|
||||
* All modifications are discarded.
|
||||
* All savepoints are cleared.
|
||||
* All locks held by the transaction are released.
|
||||
|
||||
* If you roll back to a savepoint:
|
||||
* The transaction does not end.
|
||||
* Modifications before the savepoint are retained, and modifications after the savepoint are discarded.
|
||||
* Savepoints after the savepoint are cleared (excluding the savepoint itself).
|
||||
* All locks held by the transaction after the savepoint are released.
|
||||
|
||||
Example: Roll back all modifications in a transaction.
|
||||
|
||||
```sql
|
||||
obclient> SELECT * FROM t_insert;
|
||||
+------+------+-------+---------------------+
|
||||
| id | name | value | gmt_create |
|
||||
+------+------+-------+---------------------+
|
||||
| 1 | CN | 10001 | 2025-11-07 16:01:53 |
|
||||
| 2 | US | 10002 | 2025-11-07 16:01:53 |
|
||||
| 3 | EN | 10003 | 2025-11-07 16:01:53 |
|
||||
| 4 | JP | NULL | 2025-11-07 16:02:02 |
|
||||
+------+------+-------+---------------------+
|
||||
4 rows in set
|
||||
|
||||
obclient> BEGIN;
|
||||
Query OK, 0 rows affected
|
||||
|
||||
obclient> INSERT INTO t_insert(id, name, value) VALUES(5,'JP',10004),(6,'FR',10005),(7,'RU',10006);
|
||||
Query OK, 3 rows affected
|
||||
Records: 3 Duplicates: 0 Warnings: 0
|
||||
|
||||
obclient> SELECT * FROM t_insert;
|
||||
+------+------+-------+---------------------+
|
||||
| id | name | value | gmt_create |
|
||||
+------+------+-------+---------------------+
|
||||
| 1 | CN | 10001 | 2025-11-07 16:01:53 |
|
||||
| 2 | US | 10002 | 2025-11-07 16:01:53 |
|
||||
| 3 | EN | 10003 | 2025-11-07 16:01:53 |
|
||||
| 4 | JP | NULL | 2025-11-07 16:02:02 |
|
||||
| 5 | JP | 10004 | 2025-11-07 16:04:14 |
|
||||
| 6 | FR | 10005 | 2025-11-07 16:04:14 |
|
||||
| 7 | RU | 10006 | 2025-11-07 16:04:14 |
|
||||
+------+------+-------+---------------------+
|
||||
7 rows in set
|
||||
|
||||
obclient> ROLLBACK;
|
||||
Query OK, 0 rows affected
|
||||
|
||||
obclient> SELECT * FROM t_insert;
|
||||
+------+------+-------+---------------------+
|
||||
| id | name | value | gmt_create |
|
||||
+------+------+-------+---------------------+
|
||||
| 1 | CN | 10001 | 2025-11-07 16:01:53 |
|
||||
| 2 | US | 10002 | 2025-11-07 16:01:53 |
|
||||
| 3 | EN | 10003 | 2025-11-07 16:01:53 |
|
||||
| 4 | JP | NULL | 2025-11-07 16:02:02 |
|
||||
+------+------+-------+---------------------+
|
||||
4 rows in set
|
||||
```
|
||||
|
||||
For more information about transaction control statements, see [Transaction management overview](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001971667).
|
||||
|
||||
## Create a user
|
||||
|
||||
Use the `CREATE USER` statement to create a user.
|
||||
|
||||
Example:
|
||||
|
||||
Create a user named `test`.
|
||||
|
||||
```shell
|
||||
obclient> CREATE USER 'test' IDENTIFIED BY '******';
|
||||
Query OK, 0 rows affected
|
||||
```
|
||||
|
||||
For more information about the `CREATE USER` statement, see [CREATE USER](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974176).
|
||||
|
||||
## Grant user privileges
|
||||
|
||||
Use the `GRANT` statement to grant privileges to a user.
|
||||
|
||||
Example:
|
||||
|
||||
Grant the user `test` the privilege to access all tables in the database `db1`.
|
||||
|
||||
```shell
|
||||
obclient> GRANT SELECT ON db1.* TO test;
|
||||
Query OK, 0 rows affected
|
||||
```
|
||||
|
||||
Check the privileges of the user `test`.
|
||||
|
||||
```shell
|
||||
obclient> SHOW GRANTS for test;
|
||||
+-----------------------------------+
|
||||
| Grants for test@% |
|
||||
+-----------------------------------+
|
||||
| GRANT USAGE ON *.* TO 'test' |
|
||||
| GRANT SELECT ON `db1`.* TO 'test' |
|
||||
+-----------------------------------+
|
||||
2 rows in set
|
||||
```
|
||||
|
||||
For more information about the `GRANT` statement, see [GRANT](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974144).
|
||||
|
||||
## Delete a user
|
||||
|
||||
Use the `DROP USER` statement to delete a user.
|
||||
|
||||
Example:
|
||||
|
||||
Delete the user `test`.
|
||||
|
||||
```shell
|
||||
obclient> DROP USER test;
|
||||
Query OK, 0 rows affected
|
||||
```
|
||||
|
||||
For more information about the `DROP USER` statement, see [DROP USER](https://en.oceanbase.com/docs/common-oceanbase-database-10000000001974172).
|
||||
Reference in New Issue
Block a user