Insert data

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

Prerequisites

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

• You have logged on to an Oracle tenant of OceanBase Database. For more information about how to connect to OceanBase Database, see Connection methods.

  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. For more information about how to view your privileges, see View user privileges. If you do not have the required privileges, contact the administrator. For more information, see Modify user privileges.

Use an INSERT statement to insert data

You can use the INSERT statement to insert data into a table.

The syntax is as follows:

INSERT INTO table_name (list_of_columns) VALUES (list_of_values);

Suggestions on data insertion

• 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 [SYS]> DESC ordr;
  +-------+--------------+------+-----+---------+-------+
  | FIELD | TYPE         | NULL | KEY | DEFAULT | EXTRA |
  +-------+--------------+------+-----+---------+-------+
  | C1    | NUMBER       | YES  | NULL | NULL    | NULL  |
  | C2    | VARCHAR2(50) | YES  | NULL | NULL    | NULL  |
  +-------+--------------+------+-----+---------+-------+
  2 rows in set
  

  • For a NOT NULL column, note that:

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

    • 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 do not need 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 query the NOT NULL, PRIMARY KEY, and UNIQUE constraints by using the DESC statement. The FOREIGN KEY and CHECK constraints can be queried in views ALL_CONSTRAINTS, DBA_CONSTRAINTS, and USER_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 in batches.

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

obclient [SYS]> CREATE TABLE t_insert(
    id number NOT NULL PRIMARY KEY,
    name varchar(10) NOT NULL,
    value number,
    gmt_create DATE NOT NULL DEFAULT sysdate
 );
Query OK, 0 rows affected

The id and name columns of the table cannot be empty. The id column is the primary key column with a UNIQUE constraint, and therefore cannot have duplicate values. 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 is specified for the gmt_create column. Therefore, you do not need to specify a value for this column when you insert data.

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

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

Insert multiple rows of data in batches

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 in batches.

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

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

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

obclient [SYS]> SELECT * FROM t_insert;
+----+------+-------+------------+
| ID | NAME | VALUE | GMT_CREATE |
+----+------+-------+------------+
|  1 | CN   | 10001 | 31-OCT-22  |
|  2 | US   | 10002 | 31-OCT-22  |
|  3 | EN   | 10003 | 31-OCT-22  |
+----+------+-------+------------+
3 rows in set

obclient [SYS]> CREATE TABLE t_insert_bak(
    id number NOT NULL PRIMARY KEY,
    name varchar(10) NOT NULL,
    value number,
    gmt_create DATE NOT NULL DEFAULT sysdate
 );
Query OK, 0 rows affected

obclient [SYS]> INSERT INTO t_insert_bak SELECT * FROM t_insert;
Query OK, 2 rows affected
Records: 3  Duplicates: 0  Warnings: 0

obclient [SYS]> SELECT * FROM t_insert_bak;
+----+------+-------+------------+
| ID | NAME | VALUE | GMT_CREATE |
+----+------+-------+------------+
|  1 | CN   | 10001 | 31-OCT-22  |
|  2 | US   | 10002 | 31-OCT-22  |
|  3 | EN   | 10003 | 31-OCT-22  |
+----+------+-------+------------+
3 rows in set

Use the MERGE INTO statement to insert data

In a batch processing task, a large number of INSERT operations may need to be performed on the target table. If the to-be-inserted records in the source table do not exist in the destination table, you can also use the MERGE INTO statement to insert the records of the source table into the destination table. For more information, see Replace data.

Use the INSERT statement to insert data through a DBLink

The current OceanBase Database version allows you to connect to an Oracle tenant of OceanBase Database or an Oracle database through a DBLink and write data to the database.

The following example shows how to insert a row (11,11) into the t1 table in the remote database connected through a DBLink:

obclient> SELECT * FROM t1@ob_dblink;
+------+------+
| C1   | C2   |
+------+------+
|    1 |    1 |
+------+------+
1 row in set

obclient> INSERT INTO t1@ob_dblink VALUES (11,11);
Query OK, 1 row affected

obclient> commit;
Query OK, 0 rows affected

obclient> SELECT * FROM t1@ob_dblink;
+------+------+
| C1   | C2   |
+------+------+
|    1 |    1 |
|   11 |   11 |
+------+------+
2 rows in set

References

• Update data

• Delete data

• Replace data

• Use a DBLink to modify data in a remote database