Candidate Key Profile Request Options (Data Profiling Task)
Use the Request Properties pane of the Profile Requests page to set the options for the Candidate Key Profile Request that is selected in the requests pane. A Candidate Key profile reports whether a column or set of columns is a key, or an approximate key, for the selected table. This profile can also help you identify problems in your data such as duplicate values in a potential key column.
Note
The options described in this topic appear on the Profile Requests page of the Data Profiling Task Editor. For more information about this page of the editor, see Data Profiling Task Editor (Profile Requests Page).
For more information about how to use the Data Profiling Task, see Setting Up the Data Profiling Task. For more information about how to use the Data Profile Viewer to analyze the output of the Data Profiling Task, see Viewing Profile Output in the Data Profile Viewer.
Understanding the Selection of Columns for the KeyColumns Property
Each Candidate Key Profile Request computes the key strength of a single key candidate that consists of a single column or of multiple columns:
When you select only one column in KeyColumns, the task computes the key strength of that one column.
When you select multiple columns in KeyColumns, the task computes the key strength of the composite key that consists of all the selected columns.
When you select the wildcard character, (*), in KeyColumns, the task computers the key strength of each column in the table or view.
For example, consider a sample table that contains columns A, B, and C. You make the following selections for KeyColumns:
You select (*) and column C in KeyColumns. The task computes the key strength of column C, and then of composite key candidates (A, C) and (B, C).
You select (*) and (*) in KeyColumns. The task computes the key strength of individual columns A, B, and C, and then of composite key candidates (A, B), (A, C) and (B, C).
Note
If you select (*), this option might result in a large number of computations and decrease the performance of the task. However, if the task finds a subset that satisfies the threshold for a key, the task does not analyze additional combinations. For example, in the sample table described above, if the task determines that column C is a key, the task does not continue to analyze the composite key candidates.
Request Properties Options
For a Candidate Key Profile Request, the Request Properties pane displays the following groups of options:
Data, which includes the TableOrView and KeyColumns options
General
Options
Data Options
ConnectionManager
Select the existing ADO.NET connection manager that uses the .NET Data Provider for SQL Server (SqlClient) to connect to the SQL Server database that contains the table or view to be profiled.TableOrView
Select the existing table or view to be profiled.For more information, see the section, "TableorView Options," in this topic.
KeyColumns
Select the existing column or columns to be profiled. Select (*) to profile all columns.For more information, see the sections, "Understanding the Selection of Columns for the KeyColumns Property" and "KeyColumns Options," in this topic.
TableOrView Options
Schema
Specify the schema to which the selected table belongs. This option is read-only.Table
Displays the name of the selected table. This option is read-only.
KeyColumns Options
The following options are presented for each column selected for profiling in KeyColumns, or for the (*) option.
For more information, see the section, "Understanding the Selection of Columns for the KeyColumns Property," earlier in this topic.
IsWildcard
Specifies whether the (*) wildcard has been selected. This option is set to True if you have selected (*) to profile all columns. It is False if you have selected an individual column to be profiled. This option is read-only.ColumnName
Displays the name of the selected column. This option is blank if you have selected (*) to profile all columns. This option is read-only.StringCompareOptions
Select options for comparing string values. This property has the options listed in the following table. The default value of this option is Default.Note
When you use a (*) wildcard for ColumnName, CompareOptions is read-only and is set to the Default setting.
Value
Description
Default
Sorts and compares data based on the column's collation in the source table.
BinarySort
Sorts and compares data based on the bit patterns defined for each character. Binary sort order is case sensitive and accent sensitive. Binary is also the fastest sorting order.
DictionarySort
Sorts and compares data based on the sorting and comparison rules as defined in dictionaries for the associated language or alphabet.
If you select DictionarySort, you can also select any combination of the options listed in the following table. By default, none of these additional options are selected.
Value
Description
IgnoreCase
Specifies whether the comparison distinguishes between uppercase and lowercase letters. If this option is set, the string comparison ignores case. For example, "ABC" becomes the same as "abc".
IgnoreNonSpace
Specifies whether the comparison distinguishes between spacing characters and diacritics. If this option is set, the comparison ignores diacritics. For example, "å" is equal to "a".
IgnoreKanaType
Specifies whether the comparison distinguishes between the two types of Japanese kana characters: hiragana and katakana. If this option is set, the string comparison ignores kana type.
IgnoreWidth
Specifies whether the comparison distinguishes between a single-byte character and the same character when it is represented as a double-byte character. If this option is set, the string comparison treats single-byte and double-byte representations of the same character as identical.
General Options
- RequestID
Type a descriptive name to identify this profile request. Typically, you do not have to change the autogenerated value.
Options
ThresholdSetting
This property has the options listed in the following table. The default value of this property is Specified.Value
Description
None
No threshold is specified. The key strength is reported regardless of its value.
Specified
A threshold is specified in KeyStrengthThreshold. The key strength is reported only if it is greater than the threshold.
Exact
No threshold is specified. The key strength is reported only if the selected columns are an exact key.
KeyStrengthThreshold
Specify the threshold (by using a value between 0 and 1) above which the key strength should be reported. The default value of this property is 0.95. This option is enabled only when Specified is selected as the KeyStrengthThresholdSetting.MaxNumberOfViolations
Specify the maximum number of candidate key violations to report in the output. The default value of this property is 100. This option is disabled when Exact is selected as the KeyStrengthThresholdSetting.