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DMSCHEMA_MINING_STRUCTURE_COLUMNS Rowset

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更新日期： 2006 年 4 月 14 日

Describes the individual columns of all mining structures deployed on a server that is running Microsoft SQL Server 2005 Analysis Services (SSAS).

Rowset Columns

The DMSCHEMA_MINING_STRUCTURE_COLUMNS rowset contains the following columns.

Column name Type indicator Length Description

STRUCTURE_CATALOG

DBTYPE_WSTR

The catalog name.

STRUCTURE_SCHEMA

DBTYPE_WSTR

The unqualified schema name. Analysis Services does not support schemas, so this column is always NULL.

STRUCTURE_NAME

DBTYPE_WSTR

The structure name. This column cannot contain a NULL.

COLUMN_NAME

DBTYPE_WSTR

The name of the column. Uniqueness is only guaranteed among columns that share the same pattern. For example, two nested columns may have the same name if they belong to two different nested tables inside the same structure.

COLUMN_GUID

DBTYPE_GUID

The column GUID. Providers that do not use GUIDs to identify columns should return NULL in this column.

COLUMN_PROPID

DBTYPE_UI4

The column property ID. Providers that do not associate property IDs with columns should return NULL in this column. SQL Server 2005 Analysis Services returns NULL for this column.

ORDINAL_POSITION

DBTYPE_UI4

The ordinal of the column. Columns are numbered starting from 1. NULL if there is no stable ordinal value for the column.

COLUMN_HASDEFAULT

DBTYPE_BOOL

A Boolean that indicates whether this column has a default value.

TRUE if the column has a default value.

FALSE if the column does not have a default value or if it is unknown whether the column has a default value.

COLUMN_DEFAULT

DBTYPE_WSTR

The default value of the column. A provider may expose DBCOLUMN_DEFAULTVALUE but not DBCOLUMN_HASDEFAULT (for SQL-92 tables) in the rowset returned by IColumnsRowset::GetColumnsRowset.

If the default value is NULL, COLUMN_HASDEFAULT is TRUE and the COLUMN_DEFAULT column is a NULL value.

COLUMN_FLAGS

DBTYPE_UI4
  • A bitmask that describes column characteristics. The DBCOLUMNFLAGS enumerated type specifies the bits in the bitmask. This column cannot contain a NULL value. Valid values include:
  • DBCOLUMNFLAGS_ISNULLABLE (0x20)
  • DBCOLUMNFLAGS_MAYBENULL (0x40)
  • DBCOLUMNFLAGS_ISLONG (0x80)

IS_NULLABLE

DBTYPE_BOOL

A Boolean that indicates whether this column has a default value.

TRUE if the column can contain NULL; FALSE, otherwise.

DATA_TYPE

DBTYPE_UI2

The indicator of the column's data type. For example:

  • "TABLE" = DBTYPE_HCHAPTER
  • "TEXT" = DBTYPE_WCHAR
  • "LONG" = DBTYPE_I8
  • "DOUBLE" = DBTYPE_R8
  • "DATE" = DBTYPE_DATE

TYPE_GUID

DBTYPE_GUID

The GUID of the column's data type. Providers that do not use GUIDs to identify data types should return NULL in this column.

CHARACTER_MAXIMUM_LENGTH

DBTYPE_UI4

The maximum possible length of a value in the column. For character, binary, or bit columns, this is one of the following:

  • The maximum length of the column in characters, bytes, or bits, respectively, if the length is defined. For example, a CHAR(5) column in an SQL table has a maximum length of 5.
  • The maximum length of the data type in characters, bytes, or bits, respectively, if the column does not have a defined length.
  • Zero (0) if neither the column nor the data type has a defined maximum length.
  • NULL for all other types of columns.

CHARACTER_OCTET_LENGTH

DBTYPE_UI4

The maximum length in octets (bytes) of the column, if the type of the column is character or binary. A value of zero (0) means the column has no maximum length. NULL for all other types of columns.

NUMERIC_PRECISION

DBTYPE_UI2

The maximum precision of the column if the column's data type is of a numeric data type other than VARNUMERIC; NULL if the column's data type is not numeric or is VARNUMERIC.

The precision of columns with a data type of DBTYPE_DECIMAL or DBTYPE_NUMERIC depends on the definition of the column.

NUMERIC_SCALE

DBTYPE_I2

The number of digits to the right of the decimal point if the column's type indicator is DBTYPE_DECIMAL, DBTYPE_NUMERIC, or DBTYPE_VARNUMERIC. Otherwise, this is NULL.

DATETIME_PRECISION

DBTYPE_UI4

The DateTime precision (the number of digits in the fractional seconds portion) of the column if the column is a datetime or interval type. If the column's data type is not datetime, this is NULL.

CHARACTER_SET_CATALOG

DBTYPE_WSTR

The catalog name in which the character set is defined. NULL if the provider does not support catalogs or different character sets.

CHARACTER_SET_SCHEMA

DBTYPE_WSTR

The unqualified schema name in which the character set is defined. NULL if the provider does not support schemas or different character sets.

CHARACTER_SET_NAME

DBTYPE_WSTR

The character set name. NULL if the provider does not support different character sets.

COLLATION_CATALOG

DBTYPE_WSTR

The catalog name in which the collation is defined. NULL if the provider does not support catalogs or different collations.

COLLATION_SCHEMA

DBTYPE_WSTR

The unqualified schema name in which the collation is defined. NULL if the provider does not support schemas or different collations.

COLLATION_NAME

DBTYPE_WSTR

The collation name. NULL if the provider does not support different collations.

DOMAIN_CATALOG

DBTYPE_WSTR

The catalog name in which the domain is defined. NULL if the provider does not support catalogs or domains.

DOMAIN_SCHEMA

DBTYPE_WSTR

The unqualified schema name in which the domain is defined. NULL if the provider does not support schemas or domains.

DOMAIN_NAME

DBTYPE_WSTR

The domain name. NULL if the provider does not support domains.

DESCRIPTION

DBTYPE_WSTR

A human-readable description of the column. NULL if there is no description associated with the column.

DISTRIBUTION_FLAG

DBTYPE_WSTR

The distribution of the mining structure column:

  • "NORMAL"
  • "LOG_NORMAL"
  • "UNIFORM"

CONTENT_TYPE

DBTYPE_WSTR

The content type of the mining structure column:

  • "KEY"
  • "DISCRETE"
  • "CONTINUOUS"
  • "DISCRETIZED([args])"
  • "ORDERED"
  • "SEQUENCE_TIME"
  • "CYCLICAL"
  • "PROBABILITY"
  • "VARIANCE"
  • "STDEV"
  • "SUPPORT"
  • "PROBABILITY_VARIANCE"
  • "PROBABILITY_STDEV"

MODELING_FLAG

DBTYPE_WSTR

A comma-delimited list of modeling flags. The only supported flag for a structure column is "NOT NULL".

IS_RELATED_TO_KEY

DBTYPE_BOOL

A Boolean that indicates whether this column is related to the key.

VARIANT_TRUE if this column is related to the key; VARIANT_FALSE otherwise. If the key is a single column, the RELATED_ATTRIBUTE field optionally may contain its column name.

RELATED_ATTRIBUTE

DBTYPE_WSTR

The name of the target column that the current column relates to, or is a special property of.

CONTAINING_COLUMN

DBTYPE_WSTR

The name of the TABLE column containing this column. NULL if no table contains the column.

IS_POPULATED

DBTYPE_BOOL

A Boolean that indicates whether this column has learned a set of possible values.

TRUE if the column has learned a set of possible values; FALSE, otherwise.

Restriction Columns

The DMSCHEMA_MINING_STRUCTURE_COLUMNS rowset can be restricted on the columns in the following table.

Column name Type indicator Restriction State

STRUCTURE_CATALOG

DBTYPE_WSTR

Optional.

STRUCTURE_SCHEMA

DBTYPE_WSTR

Optional.

STRUCTURE_NAME

DBTYPE_WSTR

Optional.

COLUMN_NAME

DBTYPE_WSTR

Optional.

Change History

Release History

2006 年 4 月 14 日
Changed content:
  • Updated technical information in many of the column descriptions.

请参阅

参考

Data Mining Schema Rowsets

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