Viewing Data Sources and Tables


For most directives in SAS Data Loader, data sources are Hive schemas that contain one or more tables. Data sources are defined in Hive by your Hadoop administrator. If you do not see the data source or table that you need, contact your Hadoop administrator. If needed, the administrator can add a new Hive schema and set appropriate user permissions to read and write data.
In some cases, data sources are not based on Hive schemas. For example, data sources for the Copy Data to Hadoop directive are RDBMS connections. Data sources for the Import a File directive are delimited files that are stored in the shared folder of the vApp.
When you open a directive to create a job that runs in Hadoop, you select a data source and a source table that is contained within that data source. If the directive produces output tables, you then select a data source and a target table at the end of the directive.
To protect your data, target tables do not overwrite source tables. Target tables are not required to be new tables each time you run your job. You can overwrite target tables that you created in previous job runs.
As the data is processed in each task in the job, you can view a sample of the data that is produced in each task.
A typical Source Table task includes a graphical view of the tables in the selected data source.
A typical Source Table task
SAS Table Viewer icon SAS Table Viewer icon
Click to open the selected table in the SAS Table Viewer, which provides column information and sample data for the table.
View Data Sample icon View Data Sample icon
Click to display the first 100 rows of source data, as that data has been transformed up to that point in the job.
View List icon and View Grid icon
Click the View List icon to display data sources or tables as a list. When you view tables, the list format displays the table name and description, along with the dates on which the table was last profiled and last modified.
Note: The last modified date is displayed only when the Identify each table as "new" when created or modified setting is selected on the General Preferences panel of the Configuration window. For more information, see General Preferences Panel.
Click the View Grid icon to display data sources or tables in a grid.
View Profile icon
Click to view profile information for the selected table. If a profile exists for a table, PROFILED appears beneath the table name.
Return to Data Sources Icon
Click to select a source table from another data source.
Select Recent Table icon
Click to choose from a list of recently used tables. If you select a table from a different data source, the source table information is adjusted accordingly. The table that you selected is automatically highlighted.
Screenshot of search field
Enter text in the search field to filter the list of data sources or tables. The search feature filters according to name when applied to data sources and according to name and description when applied to tables.
Return to Top icon
Click to return to the top of the page when viewing a long list of data sources or tables.
If you frequently work with the same data source across multiple directives, you can have SAS Data Loader select the most recently used schema automatically. This can help you select source tables and target tables more quickly. To enable this feature, click More icon, select Configuration, and complete the following steps:
  1. Click General Preferences.
  2. Select Automatically select the most recently selected hive schema.

About the SAS Table Viewer

How It Works

The SAS Table Viewer displays sample data and column information for a selected table. The viewer is available when you select source or target tables or when you view results or status. The SAS Table Viewer opens in a separate tab in the browser, so you can continue to reference that information while working with directives.
To open the viewer, click the Open the selected table in the table viewer icon icon for SAS Table Viewer .
SAS Table Viewer
In the viewer, you can click a column name to display the properties of that column. You can also clear the check box next to the column name to temporarily remove that column from the sample data view.
To change the number of sample rows that are displayed, change the value of the Row Limit field.
To refresh the sample data after a directive has operated on that table, click the Refresh iconRefresh icon .
Column properties are defined as follows:
Column number.
A shortened version of the column name that can be added to the data values for that column. If a label is not assigned, then the column name is used as the label.
The size of the table cell (or variable value) in bytes.
Column name.
The type of the data in the column.
For information about data types and data conversions in SAS and Hadoop, see the chapter SAS/ACCESS Interface to Hadoop in the document SAS/ACCESS Interface to Relational Databases: Reference.

Usage Notes

  • When viewing a SQL Server table, the following numeric data types are displayed in the Columns list with a character data type: datetime (datetime_col), money (money_col), smallmoney (smallmoney_col), numeric (numeric_col), and real (real_col).
  • Viewing the source and target tables of transformations can show differences in decimal values. The source columns show no decimal values, and the target shows full double-precision values. This difference exists in the display only. In the Hadoop file system HDFS, the values are the same.

About the Sample Table Viewer

In directives that list tables for selection, you can click the View a data sample icon View a data sample icon to display a subset of the source data, as that data has been transformed up to that point in the job. This gives you a preview of your data before you run your job against the full source table in Hadoop.
Sample Data Display
In the data sample, you can click Refresh to display the latest data or click X to close the data sample.