Function of Field
Captures all the columns used or referenced in a captured query plan.
Field Table Definition
The following CREATE TABLE request defines the Field table:
CREATE TABLE Field ( FieldID INTEGER NOT NULL, RelationKey INTEGER NOT NULL, Name VARCHAR(128) CHARACTER SET UNICODE NOT CASESPECIFIC, FldAlias VARCHAR(128) CHARACTER SET UNICODE NOT CASESPECIFIC, QueryID INTEGER NOT NULL, ValueAccessFrequency INTEGER, JoinAccessFrequency INTEGER, RangeAccessFrequency INTEGER, ChangeRate INTEGER, DataLength INTEGER, StatsKind CHARACTER(1) CHARACTER SET LATIN NOT CASESPECIFIC, NumNulls FLOAT, NumIntervals INTEGER, MinValue VARCHAR(512) CHARACTER SET UNICODE NOT CASESPECIFIC, ModeValue VARCHAR(512) CHARACTER SET UNICODE NOT CASESPECIFIC, ModeFreq FLOAT, TotalValues FLOAT, TotalRows FLOAT) PRIMARY INDEX(RelationKey) UNIQUE INDEX USK_FieldID_RelationKey (FieldID, RelationKey);
Attribute Definitions for Field
The following table defines the Field table attributes:
Attribute | Definition |
---|---|
FieldID |
|
RelationKey |
|
Name | The name of the captured column. |
FldAlias |
|
QueryID | The unique ID for the query. |
ValueAccessFrequency | The number of times the column is used with an equality condition. |
JoinAccessFrequency | The number of times the column is used in a join condition. |
RangeAccessFrequency | The number of times the column is used in a range condition. |
ChangeRate | The change rating value for the column.
|
DataLength | The maximum length of the column. |
StatsKind | Defines whether the statistics are collected from the dictionary or from a QCD. The data for this column is retrieved from interval 0 of the available statistics. The column is set to null if no statistics are available for the column or index. |
NumNulls | Number of nulls for the column or index. The data for this column is retrieved from interval 0 of the available statistics. The column is set to null if no statistics are available. |
NumIntervals | Number of intervals for the column or index. The data for this column is retrieved from interval 0 of the available statistics. The column is set to null if no statistics are available. |
MinValue | Minimum value for the interval. The data for this column is retrieved from interval 0 of the available statistics. The column is set to null if no statistics are available. |
ModeValue | Modal value for the interval. The data for this column is retrieved from interval 0 of the available statistics. The column is set to null if no statistics are available. |
ModeFreq | Number of occurrences of the modal value in the interval. The data for this column is retrieved from interval 0 of the available statistics. The column is set to null if no statistics are available. |
TotalValues | Number of unique values for the column or index in the table. The data for this column is retrieved from interval 0 of the available statistics. The column is set to null if no statistics are available. |
TotalRows | Cardinality of the table. The data for this column is retrieved from interval 0 of the available statistics. The column is set to null if no statistics are available. |