Creating a Partitioned Table

Partitioning refers to splitting what is logically one large table into smaller physical pieces based on specific schemes. The table based on the logic is called a partitioned table, and a physical piece is called a partition. Data is stored on these smaller physical pieces, namely, partitions, instead of the larger logical partitioned table.

Follow the steps below to define a table in your database:

In the Object Browser pane, right-click Regular Tables, and choose Create Partition Table.
Define basic table information, such as the table name and table type. For details, see Providing Basic Information.
Define column information, such as the column name, data type schema, data type, and column constraint. For details, see Defining a Column.
Select the data distribution information for the table. For details, see Configuring Data Distribution.
Define column constraints for different constraint types. Constraint types include PRIMARY KEY, UNIQUE, and CHECK. For details, see Defining Table Constraints.
Define table index information, such as the index name and access mode. For details, see Defining an Index.
Define the partition information for the table such as partition name, partition column, partition value and so on. For details, see Defining a Partition.
On the SQL Preview tab, you can check the automatically generated SQL query. For details, see SQL Preview.
To add comments to Column in the Create Partition Table dialog box, add column information in Description of Column (Max 5000 chars) text box and click Add.

Providing Basic Information

If you create a table in a schema, the current schema will be used as the schema of the table. Perform the following steps to create a partitioned table:

Select a table storage mode from the Table Orientation drop-down list.

If table orientation is selected as ORC, then an HDFS Partitioned table is created. Enter the ORC version number in the ORC Version field.

After providing the general information about the table, click Next to define the columns information for the table.

The following table describes the parameters of partitioned tables.

**Table 1** Parameters
Parameter	Row Partition	Column Partition	ORC Partition
Table Type	x	x	x
If Not Exists	√	√	√
With OIDS	x	x	x
Fill Factor	√	x	x

Defining a Column

The following table describes the parameters of partitioned tables.

**Table 2** Parameters
Parameter	Row Partition	Column Partition	ORC Partition
Array Dimensions	√	x	x
Data Type	√	x	x
NOT NULL	√	√	√
Default	√	√	√
UNIQUE	√	x	x
CHECK	√	x	x

You can add, delete, and edit columns, and adjust the sequence of columns.

You can change the order of partitions in the table as required. To change the order, select the required partition and click Up or Down.

Click to enlarge

SQL Preview

Data Studio generates a DDL statement based on the inputs provided in Create New table wizard.

You can only view, select, and copy the query. You cannot edit the query.

To select all queries, press Ctrl+A or right-click and select Select All.
To copy the selected query, press Ctrl+C or right-click and select Copy.

Click Finish to create the table. On clicking the Finish button, the generated query will be sent to the server. Any errors are displayed in the dialog box and status bar.

Defining a Partition

The following table describes the parameters of partitioned tables.

**Table 3** Parameters
Parameter	Row Partition	Column Partition	ORC Partition
Partition Type	By Range	By Range	By Value
Partition Name	√	√	x
Partition Value	√	√	x

If Row or Column is selected for Table Orientation on the General tab, By Range will be displayed in the Partition Type area. If ORC is selected for Table Orientation on the General tab, By Value will be displayed in the Partition Type area.
In the Available Column area, select a column and click the Right Arrow button. The column will be moved to the Partition Column area.
- If Table Orientation is set to Row or Column, only one column can be selected for partitioning.
- If Table Orientation is set to ORC, up to four columns can be selected for partitioning.
- A maximum of four columns can be selected to define partitions.
Enter a partition name.
Click the Enter Partition Value button next to Partition Value. Enter the value by which you want to partition the table in Value column. Click OK.
After you enter all information for partition, click Add.
You can add, delete, edit and move a column.

Change the partition sequence according to the requirements in the table. To change the order, select the required partition and click Up or Down.
After defining all partitions, click Next.

Defining an Index

For details about index definitions, see Defining an Index.

**Table 4** Parameters
Parameter	Row-store Table	Column-store Table	ORC Table
Unique Indexes	√	x	x
btree	√	√	x
gin	√	√	x
gist	√	√	x
hash	√	√	x
psort	√	√	x
spgist	√	√	x
Fill Factor	√	x	x
User Defined Expression	√	x	x
Partial Index	√	x	x

Defining Table Constraints

For details about how to define table constraints, see Defining Table Constraints.

**Table 5** Parameters
Parameter	Row Partition	Column Partition	ORC Table
Check	√	x	x
Unique	√	x	x
Primary Key	√	x	x

Configuring Data Distribution

For details about how to configure a distribution type, see Selecting Data Distribution.

**Table 6** Parameters
Parameter	Row Partition	Column Partition	ORC Partition
DEFAULT DISTRIBUTION	√	√	x
Hash	√	√	√
Replication	√	√	x

Dropping a Partition

Right-click the selected index and select Drop Partition.
Drop Partition Table dialog box is displayed.
Click OK.
The partition is deleted from the table. Data Studio displays the status of the operation in the status bar.

Renaming a partition

Right-click the selected partition and select Rename Partition.
Rename Partition Table dialog box is displayed prompting you to provide the new name for the partition.
Enter new name and click OK.
Data Studio displays the status of the operation in the status bar.