Basic data statistics
DQO provides you with summary information about your tables and columns through basic statistics. This information is valuable in deciding which data quality checks and threshold levels should be set to monitor data quality.
You have the option to collect statistics either on the table or column summary view or on an individual column level.
The table or column summary statistics include the following fields:
- Total rows: The number of rows in the table (displayed only in table-level view).
- Column name: The name of the column in the selected table. Clicking on the column name will lead you to the detailed statistics.
- Detected data type: The data type detected for STRING columns, which can be INTEGER, FLOAT, DATETIME, TIMESTAMP, BOOLEAN, STRING, or Mixed data types.
- Imported data type: The physical data type retrieved from the database metadata, specific to the data source.
- Length: The number of bytes used to store the number for numeric data types. For VARCHAR and CHAR, the length of a character string is the number of bytes.
- Scale: The number of digits to the right of the decimal point in a number.
- Minimal value: The smallest value in the column.
- Null count: The number of null values in the column.
- Null percent: The percentage of null values in the column.
- Unique count: The number of unique values in the column. The color of the field indicates the relative number of unique values and helps identify low-cardinality columns.
- Action: Buttons that allow you to collect statistics for the individual column or delete the column.
At the level of a single column, statistics provide more information and are grouped into:
- Null values: Displays the null and not-null count and percentage.
- Distinct and duplicate values
- Basic statistics: Shows minimum, median, maximum, and sum.
- String length: For string data types, shows the minimum, mean, and maximum length of the string values.
- Top 10 values: Shows the top most popular values in the column.
Note that the results displayed may vary depending on the data type.
Collect and view statistics
To collect and view statistics follow these steps:
Navigate to the Profiling section.
Select the desired data source from the tree view on the left.
Choose a table or column for which you wish to collect statistics. The Basic data statistics tab is the default for this section.
To collect statistics for the entire table, click the Collect statistics button in the upper right-hand corner. To collect statistics for a single column, click the bar chart icon located in the Action column.
Upon completion of the statistics collection, the results will be displayed. You can filter the columns by simply clicking on the sorting icon next to any column header
To view detailed statistics, click on the name of the column or navigate to the single column on the tree view.