Hologres:Manage internal tables

Create an internal table

1. Log on to the Hologres management console.

2. In the top navigation bar, select a region.

3. Click Go to HoloWeb to open the HoloWeb developer page.

4. In the top navigation bar of the HoloWeb development page, click Metadata Management. You can create an internal table in one of the following ways:

   • Method 1: Click Create Table.

   • Method 2: Right-click the target schema or Table under the schema and select Create Internal Table.

5. On the Create Internal Table page, configure the parameters.

   Category	Parameter	Description
   Basic properties	Schema	The name of the schema. You can select the default public schema or a new schema.
   	Table name	The name of the internal table.
   	Description	An optional description of the table.
   Field	Field name	The name of the field.
   	Data type	The type of values that the field can store.
   	Primary key	The unique identifier for each row of data in the table.
   	Nullable	Specifies whether the field can contain null values.
   	Array	An ordered sequence of elements.
   	Description	An optional description of the field.
   	Operations	Includes Delete, Up, and Down.
   Properties	Storage mode	The valid values are Column-oriented Storage, Row-oriented Storage, and Row-column Storage. The default value is Column-oriented Storage.
   	Data lifecycle (in seconds)	The data retention period, in seconds. This period starts when data is first written to the table. After this period expires, the data is deleted at a later time. The default value is Permanent.
   	Binlog	Specifies whether to enable Binlog for the table. For more information, see Subscribe to Hologres Binlog.
   	Binlog lifecycle	The retention period of Binlog data. For more information, see Subscribe to Hologres Binlog. The default value is Permanent.
   	Distribution key	The distribution_key. For more information, see Distribution Key.
   	Segment key	The event_time_column. For more information, see Event Time Column (Segment Key).
   	Clustering key	The clustering_key. For more information, see Clustering Key.
   	Dictionary encoding columns	The dictionary_encoding_columns. For more information, see Dictionary Encoding.
   	Bitmap column	The bitmap_columns. For more information, see Bitmap Index.
   Partitioned table	Partition field	Select a partition field.

6. In the upper-right corner of the page, click Submit. After you submit the settings, refresh the corresponding schema in the left-side navigation pane to view the new internal table.

   You can click Query Table in the upper-right corner of the table editing page to open the SQL query window and run SQL statements.

Edit an internal table

1. In the left-side navigation pane, click Instances Connected to view all connected instances.

2. Under the target instance, click Database to view your databases.

3. Under the target database, expand the Schema folder and click Table to view all internal tables.

4. Right-click the target internal table and select Open Table.

5. In the upper-right corner of the page, click Edit Table.

6. At the bottom of the page, click Add Field to add table fields. You can find the generated SQL statements and view task execution details in the Operational Logs editor.

   Note

   You cannot delete existing table fields in Edit Table mode.

7. Click Commit Table to save your changes.

Delete an internal table

1. In the left-side navigation pane, find the target internal table on the Instances Connected tab.

   For more information, see Steps 1 to 3 in Edit an internal table.

2. Right-click the target internal table and select Delete Table.

3. Click OK.

Data preview

1. In the left-side navigation pane, find the target internal table on the Instances Connected tab.

   For more information, see Steps 1 to 3 in Edit an internal table.

2. Double-click the target internal table and click Data Preview on the table editing page.

   The following figure shows a sample data preview. The table displays two columns, cityid and cityname. The cityid column is selected.

DDL statements

1. In the left-side navigation pane, find the target internal table on the Instances Connected tab.

   For more information, see Steps 1 to 3 in Edit an internal table.

2. Double-click the target internal table and click DDL Statements on the table editing page.

   The following figure shows a sample DDL statement. The DDL Statements tab displays the complete CREATE TABLE statement for the public.city table. The table contains the cityid int4 and cityname varchar(20) columns. The CALL SET_TABLE_PROPERTY statement configures properties such as the storage mode (orientation is set to column), bitmap column (bitmap_columns is set to cityname), dictionary encoding columns (dictionary_encoding_columns is set to cityname:auto), data lifecycle (time_to_live_in_seconds is set to 3153600000), and storage format (storage_format is set to segment).

Related topics

You can also use SQL statements to create, modify, and delete internal tables. For more information, see the following topics:

• CREATE TABLE

• CREATE TABLE AS

• CREATE TABLE LIKE

• ALTER TABLE

• DROP TABLE

• Physical partitioned table