Create a table

ODC supports visualized table creation. This topic describes how to create a table with ODC.

Overview

OceanBase Developer Center (ODC) allows you to create a table on a GUI. This topic describes how to create a table in the ODC console.

As shown in the preceding figure, you can create a table in the following seven steps:

1. Specify the basic information.

2. Set columns.

3. Set the index.

4. Set constraints.

5. Set partitioning rules.

6. Confirm the SQL statement.

7. Complete the table creation.

Procedure

In the following example, a table named employee is created in the ODC console. The table contains the emp_no, birthdate, name, and gender columns. Perform the following operations:

Step 1: Specify the basic information

Log on to the ODC console and click the name of the desired connection to go to the corresponding connection management page. You can click Table in the left-side navigation pane to get a list of tables. To create a table, click + in the upper-right corner of the table list or click Create in the top navigation bar.

In the Basic Info section, specify Table Name and Description.

Note

In MySQL mode, you also need to specify **Default Character Set** and **Default Sorting Rule**.

After you specify the basic information and switch to the **Column** step, the basic information is submitted.

Step 2: Set columns

The following figure and table show the information that you need to specify when you add a column.

The following table describes operations that you can perform on the column setting page.

Note

After you copy a row, you can paste the row by using the Command + V or Ctrl + V shortcut keys.

The auxiliary editing section at the bottom of the page displays additional information about the selected column.

Settings in the Basic Information and Column steps are required. Settings in other configuration steps are optional. After you specify settings in the Basic Information and Column steps, you can click Commit and Confirm SQL Statement to create a table.

Step 3: Set indexes

If a table contains a large amount of data, you can use indexes to accelerate data queries. An index is a data structure that pre-sorts the values of one or more columns in a table. By using indexes, you can directly locate records that meet the conditions.

The following figure and table show the information that you need to specify when you set the index.

The index setting page provides the following icons.

Step 4: Set constraints

Constraints are used to specify data rules for a table. A data operation that violates the constraints will be terminated.

ODC supports the following four table constraints:

• Primary Key Constraint: defines a primary key to uniquely identify each row of data in the table. A primary key constraint can be a field or a group of fields. You can set only one primary key constraint for a table, and you cannot edit the constraint after it is configured.

• Unique Constraint: ensures that the data in a field or a group of fields is unique in the table. You can set multiple unique constraints in one table.

• Foreign Key Constraint: associates one or more columns in two tables. A foreign key constraint is used to maintain the data consistency and integrity between associated tables. After you complete the setting of foreign key constraints, you cannot create new constraints or edit existing constraints.

• Check Constraints: checks the data in the database based on the configured check rules when you edit the data. Data modification is allowed only after the check is passed.

OceanBase Database supports different constraints in MySQL and Oracle modes, and different constraints require different information. Therefore, you need to specify the required information based on the constraint you selected and the requirements on the page.

The constraint setting page provides the following icons.

Step 5: Set partitioning rules

You can partition a table that contains a large amount of data. After a table is partitioned, data in the table is stored in multiple tablespaces. The database does not scan the entire table for a query.

• In MySQL mode, OceanBase Database supports the following six partitioning methods: Key, Hash, Range, Range Columns, List, and List Columns.

• In Oracle mode, OceanBase Database supports the following three partitioning methods: List, Range, and Hash.

  The definition of a partition in MySQL mode is different from that in Oracle mode. So, the values of the following fields vary in different modes. You need to specify the following fields based on the selected partitioning method.

  Field	Description
  Partitioning Method	Specifies the partitioning method. The partitioning methods supported in MySQL mode are different from those in Oracle mode. - Range partitioning: Multiple rows with column values in an ordered, continuous, and non-overlapping range are assigned to a partition. - List partitioning: A table is partitioned based on the enumeration values. - Hash partitioning: A table is partitioned based on a given number of partitions. For a table that stores data without a clear pattern or range, you can use hash partitioning to randomly distribute values of the partition column to different partitions based on the HASH algorithm. - Key partitioning: This partitioning method is similar to HASH partitioning. The difference is that key partitioning only supports computation of one or more columns, and the MySQL server provides its own hash function. At least one INT type column is required for Key partitioning. For more information about partitioning, see About partitioned tables.
  Field	The column that is used as the partition key.
  Expression	Partitions are divided based on the return value of the expression. The partition expression is not supported in Oracle mode.
  Partition	Based on the value specified for Partitioning Method, you may need to specify information such as Partition Name, Partition Quantity, Upper Limit, and Value Enumeration. You can add multiple partitions and drag selected fields to adjust their order.

Step 6: Confirm the SQL statement

After you click Submit, you can view the statement on the SQL Confirmation page. To view lengthy clauses, click SQL Check and Format in the lower-right corner of the page.

Syntax:

CREATE TABLE table_name (column_name column_type, column_name column_type,.......);

Parameters

Step 7: Complete the table creation

Click Execute. After the table is created, the employee table appears in the table list in the left-side navigation pane.

Note
To manage a table, right-click the table name in the left-side navigation pane, and select the required operation from the context menu, which provides the following options: View Table Structure, View DDL, View Table Data, CreateTable, Import, Export, Download, Mock Data, Open SQL Window, Copy, Rename, Delete, and Refresh.

For more information, see Manage table data.

You can use the SELECT statement to query data in the new table.

Syntax:

SELECT
 column_name,
 column_name
FROM
 table_name [WHERE Clause] [LIMIT N] [ OFFSET M]

Parameters

Example:

SELECT `emp_no`, `birthdate`, `name`, `gender` FROM `employee`;

Related topics

• Create a view
• Create a function
• Create a stored procedure
• Create a sequence
• Create a program package
• Create a trigger
• Create a type
• Create a synonym