Insert data

After you create a table, you can use the INSERT statement or other statements to insert records into the table. This topic describes how to use related statements.

Prerequisites

Before you insert data into a table, make sure that:

• You have connected to a MySQL-compatible tenant of OceanBase Cloud.

  Note

  You can query the oceanbase.DBA_OB_TENANTS view in the sys tenant to confirm the mode of the tenant to which you have logged on.

• You have the INSERT privilege on the target table. If you do not have the required privileges, contact the administrator to obtain the privileges.

Use the INSERT INTO statement to insert data

Use the INSERT statement to insert data into a table.

The syntax of the INSERT INTO statement is as follows:

INSERT INTO table_name (list_of_columns) VALUES (list_of_values);

Considerations

• Before you insert data, we recommend that you learn the information about all columns of the table, including the column types, valid values, and whether NULL values are allowed.

  You can use the DESC statement to query information about columns.

  obclient [test]> DESC test;
  +-------+---------+------+-----+---------+-------+
  | Field | Type    | Null | Key | Default | Extra |
  +-------+---------+------+-----+---------+-------+
  | col1  | int(11) | NO   |     | NULL    |       |
  | col2  | int(11) | YES  |     | NULL    |       |
  +-------+---------+------+-----+---------+-------+
  2 rows in set
  

  • For a NOT NULL column, note that:

    • If the column has a default value, you can choose not to specify a value for this column when you insert data. The system will insert the default value into this column.

    • If no default value has been specified for the column, you must specify a value for the column when you insert data.

  • For a NULL column, you can choose not to specify a value for this column when you insert data. The system will insert a NULL value into this column.

• Before you insert data into a table, we recommend that you learn the information about constraints defined on columns of the table. This is to avoid errors when you insert data.

  You can use the DESC statement to query NOT NULL, PRIMARY KEY, and UNIQUE constraints. You can query the information_schema.TABLE_CONSTRAINTS view for FOREIGN KEY and CHECK constraints.

Insert a single row of data

You can use the INSERT statement to insert a single row of data. To insert multiple records, you can execute the single-row insertion statement multiple times. To perform batch insertion, see Insert multiple rows of data at a time.

Assume that the information about the table into which data is to be inserted is as follows:

obclient [test]> CREATE TABLE t_insert(
    id int NOT NULL PRIMARY KEY,
    name varchar(10) NOT NULL, 
    value int,
    gmt_create DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
Query OK, 0 rows affected 

The id and name columns of the table cannot be empty. The id column is the primary key column and cannot contain duplicate values because a UNIQUE constraint is defined on this column. A default value is specified for the gmt_create column.

Example 1: Insert multiple rows of data into a table by executing the single-row insertion statement multiple times.

A default value has been specified for the gmt_create column. Therefore, you can choose not to specify a value for this column when you insert data.

obclient [test]> INSERT INTO t_insert(id, name, value) 
VALUES (1,'CN',10001);
Query OK, 2 rows affected

obclient [test]> INSERT INTO t_insert(id, name, value) 
VALUES(2,'US', 10002);
Query OK, 2 rows affected

If no default value is specified for the gmt_create column, you must specify a value for this column when you insert data by using the following statement:

obclient [test]> INSERT INTO t_insert(id, name, value, gmt_create)
 VALUES (3,'EN', 10003, current_timestamp ());
Query OK, 1 row affected 

Insert multiple rows of data at a time

To insert multiple records, you can also use an INSERT statement that contains multiple VALUES. A single multi-row insertion statement is executed faster than multiple single-row insertion statements.

The operation in Example 1 can be completed by using the statement in Example 2.

Example 2: Insert multiple rows of data at a time.

obclient [test]> INSERT INTO t_insert(id, name, value) 
  VALUES (1,'CN',10001),(2,'US', 10002);
Query OK, 2 rows affected

When you need to back up the data of a table or copy all records of a table to another table, you can use the INSERT INTO ... SELECT ... FROM statement as the VALUES clause of the INSERT statement for batch insertion.

Example 3: Back up all data of the t_insert table to the t_insert_bak table.

obclient [test]> SELECT * FROM t_insert;
+----+------+-------+---------------------+
| id | name | value | gmt_create          |
+----+------+-------+---------------------+
|  1 | CN   | 10001 | 2022-10-12 15:17:17 |
|  2 | US   | 10002 | 2022-10-12 16:29:16 |
|  3 | EN   | 10003 | 2022-10-12 16:29:26 |
+----+------+-------+---------------------+
3 rows in set

obclient [test]> CREATE TABLE t_insert_bak(
    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 [test]> INSERT INTO t_insert_bak SELECT * FROM t_insert;
Query OK, 2 rows affected

obclient [test]> SELECT * FROM t_insert_bak;
+----+------+-------+---------------------+
| id | name | value | gmt_create          |
+----+------+-------+---------------------+
|  1 | CN   | 10001 | 2022-10-12 15:17:17 |
|  2 | US   | 10002 | 2022-10-12 16:29:16 |
|  3 | EN   | 10003 | 2022-10-12 16:29:26 |
+----+------+-------+---------------------+
3 rows in set

Avoid UNIQUE constraint conflicts

When you insert identical records into a table that has a UNIQUE constraint, the database returns an error. Here is the error message:

obclient [test]> INSERT INTO t_insert(id, name, value) VALUES (3,'UK', 10003),(4, 'JP', 10004);
ERROR 1062 (23000): Duplicate entry '3' for key 'PRIMARY'

You can use the INSERT IGNORE INTO or INSERT INTO ON DUPLICATE KEY UPDATE statement to avoid this error.

Here are some examples:

• If you use the INSERT IGNORE INTO statement to avoid constraint conflicts, you can use the IGNORE keyword to ignore the impact of an insertion failure caused by a constraint conflict.

  obclient [test]> INSERT IGNORE INTO t_insert(id, name, value) 
      VALUES (3,'UK', 10003),(4, 'JP', 10004);
  Query OK, 1 row affected 
  
  obclient [test]> SELECT * FROM t_insert;
  +----+------+-------+---------------------+
  | id | name | value | gmt_create          |
  +----+------+-------+---------------------+
  |  1 | CN   | 10001 | 2022-10-12 15:17:17 |
  |  2 | US   | 10002 | 2022-10-12 16:29:16 |
  |  3 | EN   | 10003 | 2022-10-12 16:29:26 |
  |  4 | JP   | 10004 | 2022-10-12 17:02:52 |
  +----+------+-------+---------------------+
  4 rows in set
  

  In this example, the INSERT IGNORE INTO statement is used. Therefore, the system does not return an error even if (3,'UK', 10003) failed to be inserted.

• If you use the INSERT INTO ON DUPLICATE KEY UPDATE statement to avoid constraint conflicts, you can specify the action to take on duplicate primary keys or unique keys.

  Note

  • ON DUPLICATE KEY UPDATE column_name = expr is specified: If the data to be inserted is duplicate with values of the primary key or unique key, you can use the column_name = expr statement to update the data in conflicting rows of the table. The column_name = expr statement can assign values to one or more columns of the conflicting rows. Separate the columns with commas (,).
  • ON DUPLICATE KEY UPDATE column_name = expr is not specified: If the data to be inserted is duplicate with values of the primary key or unique key, the system returns an error.

  obclient [test]> INSERT INTO t_insert(id, name, value) VALUES (3,'UK', 10003),(5, 'CN', 10005) ON DUPLICATE KEY UPDATE name = VALUES(name);
  Query OK, 1 row affected 
  
  obclient [test]> SELECT * FROM t_insert;
  +----+------+-------+---------------------+
  | id | name | value | gmt_create          |
  +----+------+-------+---------------------+
  |  1 | CN   | 10001 | 2022-10-12 16:29:16 |
  |  2 | US   | 10002 | 2022-10-12 15:17:17 |
  |  3 | UK   | 10003 | 2022-10-12 16:29:26 |
  |  4 | JP   | 10004 | 2022-10-12 17:02:52 |
  |  5 | CN   | 10005 | 2022-10-12 17:27:46 |
  +----+------+-------+---------------------+
  5 rows in set
  

  In this example, ON DUPLICATE KEY UPDATE name = VALUES(name) specifies that when the inserted data is duplicate with a value of the primary key, the value of the name column of the conflicting row (3,'EN', 10003) in the original data is updated to the data of the name column to be inserted. For non-conflicting rows, data is normally inserted.

Use the INSERT OVERWRITE SELECT statement to insert data

The INSERT OVERWRITE SELECT statement overwrites existing data in the target table with the query results.

The syntax is as follows:

INSERT [/*+PARALLEL(N)*/] OVERWRITE table_name select_stmt;

Limitations

• The statement cannot be executed in a multi-row transaction. Therefore, you must first execute the SET autocommit = on; statement to enable auto commit of transactions.
• The target table will be locked during the execution of this statement. During this process, you cannot initiate any DDL operations on this table. If you initiate a DML operation, it will wait for the table lock to be released, or until it times out. However, you can still initiate queries on the table during this process.
• In the current version, you can overwrite only all data in the whole table, rather than the data in specific partitions.
• The number of columns in the source data to be inserted by the statement must exactly match that in the target table. Otherwise, an error will be returned.
• The statement writes data in full direct load mode, and is therefore subject to the full direct load feature.
• If you specify a hint for direct load in this statement, an error will be returned.
• This statement is subject to the Parallel Data Manipulation Language (PDML) framework. You cannot use this statement to import data in scenarios that do not support PDML. If you do, an error will be returned.

Examples

1. Create two test tables: source_tbl1 that serves as the data source and target_tbl1 that serves as the target table.

   CREATE TABLE source_tbl1 (col1 INT, col2 VARCHAR(20), col3 INT);
   

   CREATE TABLE target_tbl1 (col1 INT, col2 VARCHAR(20), col3 INT);
   

2. Insert sample data into the source_tbl1 table.

   INSERT INTO source_tbl1 VALUES (1, 'A1', 30),(2, 'B2', 25),(3, 'C3', 22);
   

3. Insert sample data into the target_tbl1 table.

   INSERT INTO target_tbl1 VALUES (4, 'D4', 35),(5, 'E5', 28);
   

4. Query the data in the target_tbl1 table.

   SELECT * FROM target_tbl1;
   

   The return result is as follows:

   +------+------+------+
   | col1 | col2 | col3 |
   +------+------+------+
   |    4 | D4   |   35 |
   |    5 | E5   |   28 |
   +------+------+------+
   2 rows in set
   

5. Use the INSERT OVERWRITE SELECT statement to select the data whose col3 values exceed 25 from the source_tbl1 table and insert the data into the target_tbl1 table in overwriting mode.

   INSERT OVERWRITE target_tbl1 SELECT * FROM source_tbl1 WHERE col3 > 25;
   

6. Query the data in the target_tbl1 table.

   SELECT * FROM target_tbl1;
   

   The return result is as follows:

   +------+------+------+
   | col1 | col2 | col3 |
   +------+------+------+
   |    1 | A1   |   30 |
   +------+------+------+
   1 row in set
   

Use the REPLACE INTO statement to insert data

Apart from the INSERT statement, you can use the REPLACE INTO statement to insert data into a table without data records or a table with data records but no primary key or unique key conflicts.

Here are some examples:

• Create a table named t_replace and then use the REPLACE INTO statement to insert data into the table.

  obclient [test]> CREATE TABLE t_replace(
      id int NOT NULL PRIMARY KEY
      , name varchar(10) NOT NULL
      , value int
      ,gmt_create timestamp NOT NULL DEFAULT current_timestamp
  );
  Query OK, 0 rows affected 
  
  obclient [test]> REPLACE INTO t_replace VALUES(1,'CN',2001, current_timestamp ());
  Query OK, 1 row affected 
  
  obclient [test]> SELECT * FROM t_replace;
  +----+------+-------+---------------------+
  | id | name | value | gmt_create          |
  +----+------+-------+---------------------+
  |  1 | CN   |  2001 | 2022-11-23 09:52:44 |
  +----+------+-------+---------------------+
  1 row in set 
  

• Use the REPLACE INTO statement to insert data into the t_replace table that has data records.

  obclient [test]> SELECT * FROM t_replace;
  +----+------+-------+---------------------+
  | id | name | value | gmt_create          |
  +----+------+-------+---------------------+
  |  1 | CN   |  2001 | 2022-03-22 16:13:55 |
  +----+------+-------+---------------------+
  1 row in set 
  
  obclient [test]> REPLACE INTO t_replace values(2,'US',2002, current_timestamp ());
  Query OK, 1 row affected
  
  obclient [test]> SELECT * FROM t_replace;
  +----+------+-------+---------------------+
  | id | name | value | gmt_create          |
  +----+------+-------+---------------------+
  |  1 | CN   |  2001 | 2022-11-23 09:52:44 |
  |  2 | US   |  2002 | 2022-11-23 09:53:05 |
  +----+------+-------+---------------------+
  2 rows in set