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AODX Columns列的特殊属性概要

2015-12-31 / 1202次

The DBPROPSET_JETOLEDB_COLUMN property set contains the following properties.

 

Property ID

Description

DBPROP_JETOLEDB_COL_ALLOWZEROLENGTH

Type: VT_BOOL

Typical R/W: R/W

Description: Jet OLEDB:Allow Zero Length

Determines whether zero-length strings can be inserted into this field. Ignored for data types that are not strings. This is similar to the OLE DB standard property DBPROP_COL_NULLABLE but distinct. Zero-length strings are not NULLs in Jet.

DBPROP_JETOLEDB_COL_AUTOGENERATE

Type: VT_BOOL

Typical R/W: R/W

Description: Jet OLEDB:AutoGenerate

Whether a GUID should be automatically generated for the column. This property is ignored unless the underlying storage type is GUID.

DBPROP_JETOLEDB_COL_COMPRESSED

Type: VT_BOOL

Typical R/W: R/W

Description: Jet OLEDB:Compressed UNICODE Strings

Determines whether Jet should compress UNICODE strings on the disk. This applies only to the version 4.0 .mdb file format and is ignored when running against all other storage formats.

  • VARIANT_TRUE — Compress UNICODE strings.

  • VARIANT_FALSE — Do not compress UNICODE strings.

DBPROP_JETOLEDB_COL_HYPERLINK

Type: VT_BOOL

Typical R/W: R/W

Description: Jet OLEDB:Hyperlink

Whether this column is a hyperlink. This property is ignored unless the underlying storage type is LongText.

DBPROP_JETOLEDB_COL_IISAMNOTLAST

Type: VT_BOOL

Typical R/W: R/W

Description: Jet OLEDB:IISAM Not Last Column

For Installable ISAMs, this property informs the IISAM that more columns will be added to the table after this one. If you are using ITableDefinition::AddColumn or ITableDefinition::CreateTable, it is required that you set this property for every column except the last column to be added to the table.

This does not apply to the native Jet data store or any IISAM that reads previous formats of the native Jet data store.

DBPROP_JETOLEDB_COL_ONELVPERPAGE

Type: VT_BOOL

Typical R/W: R/W

Description: Jet OLEDB:One BLOB per Page

Whether BLOBs can share database pages.

  • VARIANT_TRUE — BLOBs can be stored only on their own pages.

  • VARIANT_FALSE — BLOBs can share database pages to conserve space.

DBPROP_JETOLEDB_COL_VALIDATIONRULE

Type: VT_BSTR

Typical R/W: R/W

Description: Jet OLEDB:Column Validation Rule

Expression to be evaluated on a column to validate its value before allowing it to be set. This operates in a fashion similar to SQL-92 CHECK clauses.

DBPROP_JETOLEDB_COL_VALIDATIONTEXT

Type: VT_BSTR

Typical R/W: R/W

Description: Jet OLEDB:Column Validation Text

Error string to display when the validation rule specified in DBPROP_JETOLEDB_COL_VALIDATIONRULE is not met.
 

原文地址:https://msdn.microsoft.com/en-us/library/windows/desktop/ms717947(v=vs.85).aspx
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