CDaoTableDef Class

项目
06/05/2017

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The latest version of this topic can be found at CDaoTableDef Class.

Represents the stored definition of a base table or an attached table.

Syntax

class CDaoTableDef : public CObject

Members

Public Constructors

Name	Description
CDaoTableDef::CDaoTableDef	Constructs a CDaoTableDef object.

Public Methods

Name	Description
CDaoTableDef::Append	Adds a new table to the database.
CDaoTableDef::CanUpdate	Returns nonzero if the table can be updated (you can modify the definition of fields or the table properties).
CDaoTableDef::Close	Closes an open tabledef.
CDaoTableDef::Create	Creates a table which can be added to the database using Append.
CDaoTableDef::CreateField	Called to create a field for a table.
CDaoTableDef::CreateIndex	Called to create an index for a table.
CDaoTableDef::DeleteField	Called to delete a field from a table.
CDaoTableDef::DeleteIndex	Called to delete an index from a table.
CDaoTableDef::GetAttributes	Returns a value that indicates one or more characteristics of a `CDaoTableDef` object.
CDaoTableDef::GetConnect	Returns a value that provides information about the source of a table.
CDaoTableDef::GetDateCreated	Returns the date and time the base table underlying a `CDaoTableDef` object was created.
CDaoTableDef::GetDateLastUpdated	Returns the date and time of the most recent change made to the design of the base table.
CDaoTableDef::GetFieldCount	Returns a value that represents the number of fields in the table.
CDaoTableDef::GetFieldInfo	Returns specific kinds of information about the fields in the table.
CDaoTableDef::GetIndexCount	Returns the number of indexes for the table.
CDaoTableDef::GetIndexInfo	Returns specific kinds of information about the indexes for the table.
CDaoTableDef::GetName	Returns the user-defined name of the table.
CDaoTableDef::GetRecordCount	Returns the number of records in the table.
CDaoTableDef::GetSourceTableName	Returns a value that specifies the name of the attached table in the source database.
CDaoTableDef::GetValidationRule	Returns a value that validates the data in a field as it is changed or added to a table.
CDaoTableDef::GetValidationText	Returns a value that specifies the text of the message that your application displays if the value of a Field object does not satisfy the specified validation rule.
CDaoTableDef::IsOpen	Returns nonzero if the table is open.
CDaoTableDef::Open	Opens an existing tabledef stored in the database's TableDef's collection.
CDaoTableDef::RefreshLink	Updates the connection information for an attached table.
CDaoTableDef::SetAttributes	Sets a value that indicates one or more characteristics of a `CDaoTableDef` object.
CDaoTableDef::SetConnect	Sets a value that provides information about the source of a table.
CDaoTableDef::SetName	Sets the name of the table.
CDaoTableDef::SetSourceTableName	Sets a value that specifies the name of an attached table in the source database.
CDaoTableDef::SetValidationRule	Sets a value that validates the data in a field as it is changed or added to a table.
CDaoTableDef::SetValidationText	Sets a value that specifies the text of the message that your application displays if the value of a Field object does not satisfy the specified validation rule.

Public Data Members

Name	Description
CDaoTableDef::m_pDAOTableDef	A pointer to the DAO interface underlying the tabledef object.
CDaoTableDef::m_pDatabase	Source database for this table.

Remarks

Each DAO database object maintains a collection, called TableDefs, that contains all saved DAO tabledef objects.

You manipulate a table definition using a CDaoTableDef object. For example, you can:

Examine the field and index structure of any local, attached, or external table in a database.
Call the SetConnect and SetSourceTableName member functions for attached tables, and use the RefreshLink member function to update connections to attached tables.
Call the CanUpdate member function to determine if you can edit field definitions in the table.
Get or set validation conditions using the GetValidationRule and SetValidationRule, and the GetValidationText and SetValidationText member functions.
Use the Open member function to create a table-, dynaset-, or snapshot-type CDaoRecordset object.

Note

The DAO database classes are distinct from the MFC database classes based on Open Database Connectivity (ODBC). All DAO database class names have the "CDao" prefix. You can still access ODBC data sources with the DAO classes; the DAO classes generally offer superior capabilities because they are specific to the Microsoft Jet database engine.

To use tabledef objects either to work with an existing table or to create a new table

In all cases, first construct a CDaoTableDef object, supplying a pointer to a CDaoDatabase object to which the table belongs.
Then do the following, depending on what you want:
- To use an existing saved table, call the tabledef object's Open member function, supplying the name of the saved table.
- To create a new table, call the tabledef object's Create member function, supplying the name of the table. Call CreateField and CreateIndex to add fields and indexes to the table.
- Call Append to save the table by appending it to the database's TableDefs collection. Create puts the tabledef into an open state, so after calling Create you do not call Open.
  
  Tip
  
  The easiest way to create saved tables is to create them and store them in your database using Microsoft Access. Then you can open and use them in your MFC code.

To use the tabledef object you have opened or created, create and open a CDaoRecordset object, specifying the name of the tabledef with a dbOpenTable value in the nOpenType parameter.

To use a tabledef object to create a CDaoRecordset object, you typically create or open a tabledef as described above, then construct a recordset object, passing a pointer to your tabledef object when you call CDaoRecordset::Open. The tabledef you pass must be in an open state. For more information, see class CDaoRecordset.

When you finish using a tabledef object, call its Close member function; then destroy the tabledef object.

Inheritance Hierarchy

CObject

CDaoTableDef

Requirements

Header: afxdao.h

CDaoTableDef::Append

Call this member function after you call Create to create a new tabledef object to save the tabledef in the database.

virtual void Append();

Remarks

The function appends the object to the database's TableDefs collection. You can use the tabledef as a temporary object while defining it by not appending it, but if you want to save and use it, you must call Append.

Note

If you attempt to append an unnamed tabledef (containing a null or empty string), MFC throws an exception.

For related information, see the topic "Append Method" in DAO Help.

CDaoTableDef::CanUpdate

Call this member function to determine whether the definition of the table underlying a CDaoTableDef object can be changed.

BOOL CanUpdate();

Return Value

Nonzero if the table structure (schema) can be modified (add or delete fields and indexes), otherwise 0.

Remarks

By default, a newly created table underlying a CDaoTableDef object can be updated, and an attached table underlying a CDaoTableDef object cannot be updated. A CDaoTableDef object may be updatable, even if the resulting recordset is not updatable.

For related information, see the topic "Updatable Property" in DAO Help.

CDaoTableDef::CDaoTableDef

Constructs a CDaoTableDef object.

CDaoTableDef(CDaoDatabase* pDatabase);

Parameters

pDatabase
A pointer to a CDaoDatabase object.

Remarks

After constructing the object, you must call the Create or Open member function. When you finish with the object, you must call its Close member function and destroy the CDaoTableDef object.

CDaoTableDef::Close

Call this member function to close and release the tabledef object.

virtual void Close();

Remarks

Usually after calling Close, you delete the tabledef object if it was allocated with new.

You can call Open again after calling Close. This lets you reuse the tabledef object.

For related information, see the topic "Close Method" in DAO Help.

CDaoTableDef::Create

Call this member function to create a new saved table.

virtual void Create(
    LPCTSTR lpszName,  
    long lAttributes = 0,  
    LPCTSTR lpszSrcTable = NULL,  
    LPCTSTR lpszConnect = NULL);

Parameters

lpszName
A pointer to a string containing the name of the table.

lAttributes
A value corresponding to characteristics of the table represented by the tabledef object. You can use the bitwise-OR to combine any of the following constants:

Constant	Description
dbAttachExclusive	For databases that use the Microsoft Jet database engine, indicates the table is an attached table opened for exclusive use.
dbAttachSavePWD	For databases that use the Microsoft Jet database engine, indicates that the user ID and password for the attached table are saved with the connection information.
dbSystemObject	Indicates the table is a system table provided by the Microsoft Jet database engine.
dbHiddenObject	Indicates the table is a hidden table provided by the Microsoft Jet database engine.

lpszSrcTable
A pointer to a string containing the source table name. By default this value is initialized as NULL.

lpszConnect
A pointer to a string containing the default connection string. By default this value is initialized as NULL.

Remarks

Once you have named the tabledef, you can then call Append to save the tabledef in the database's TableDefs collection. After calling Append, the tabledef is in an open state, and you can use it to create a CDaoRecordset object.

For related information, see the topic "CreateTableDef Method" in DAO Help.

CDaoTableDef::CreateField

Call this member function to add a field to the table.

void CreateField(
    LPCTSTR lpszName,  
    short nType,  
    long lSize,  
    long lAttributes = 0);  
  
void CreateField(CDaoFieldInfo& fieldinfo);

Parameters

lpszName
A pointer to a string expression specifying the name of this field.

nType
A value indicating the data type of the field. The setting can be one of these values:

Type	Size (bytes)	Description
dbBoolean	1 byte	BOOL
dbByte	1	BYTE
dbInteger	2	int
dbLong	4	long
dbCurrency	8	Currency ( COleCurrency)
dbSingle	4	float
dbDouble	8	double
dbDate	8	Date/Time ( COleDateTime)
dbText	1 – 255	Text ( CString)
dbLongBinary	0	Long Binary (OLE Object), CLongBinary or CByteArray
dbMemo	0	Memo ( CString)

lSize
A value that indicates the maximum size, in bytes, of a field that contains text, or the fixed size of a field that contains text or numeric values. The lSize parameter is ignored for all but text fields.

lAttributes
A value corresponding to characteristics of the field and that can be combined using a bitwise-OR.

Constant	Description
dbFixedField	The field size is fixed (default for Numeric fields).
dbVariableField	The field size is variable (Text fields only).
dbAutoIncrField	The field value for new records is automatically incremented to a unique long integer that cannot be changed. Only supported for Microsoft Jet database tables.
dbUpdatableField	The field value can be changed.
dbDescending	The field is sorted in descending (Z – A or 100 – 0) order (applies only to a Field object in a Fields collection of an Index object). If you omit this constant, the field is sorted in ascending (A – Z or 0 – 100) order (default).

fieldinfo
A reference to a CDaoFieldInfo structure.

Remarks

A DAOField (OLE) object is created and appended to the Fields collection of the DAOTableDef (OLE) object. Besides its use for examining object properties, you can also use CDaoFieldInfo to construct an input parameter for creating new fields in a tabledef. The first version of CreateField is simpler to use, but if you want finer control, you can use the second version of CreateField, which takes a CDaoFieldInfo parameter.

If you use the version of CreateField that takes a CDaoFieldInfo parameter, you must carefully set each of the following members of the CDaoFieldInfo structure:

m_strName
m_nType
m_lSize
m_lAttributes
m_bAllowZeroLength

The remaining members of CDaoFieldInfo should be set to 0, FALSE, or an empty string, as appropriate for the member, or a CDaoException may occur.

For related information, see the topic "CreateField Method" in DAO Help.

CDaoTableDef::CreateIndex

Call this function to add an index to a table.

void CreateIndex(CDaoIndexInfo& indexinfo);

Parameters

indexinfo
A reference to a CDaoIndexInfo structure.

Remarks

Indexes specify the order of records accessed from database tables and whether or not duplicate records are accepted. Indexes also provide efficient access to data.

You do not have to create indexes for tables, but in large, unindexed tables, accessing a specific record or creating a recordset can take a long time. On the other hand, creating too many indexes slows down update, append, and delete operations as all indexes are automatically updated. Consider these factors as you decide which indexes to create.

The following members of the CDaoIndexInfo structure must be set:

m_strName A name must be supplied.
m_pFieldInfos Must point to an array of CDaoIndexFieldInfo structures.
m_nFields Must specify the number of fields in the array of CDaoFieldInfo structures.

The remaining members will be ignored if set to FALSE. In addition, the m_lDistinctCount member is ignored during creation of the index.

CDaoTableDef::DeleteField

Call this member function to remove a field and make it inaccessible.

void DeleteField(LPCTSTR lpszName);  
void DeleteField(int nIndex);
```  
  
### Parameters  
 `lpszName`  
 A pointer to a string expression that is the name of an existing field.  
  
 `nIndex`  
 The index of the field in the table's zero-based Fields collection, for lookup by index.  
  
### Remarks  
 You can use this member function on a new object that has not been appended to the database or when [CanUpdate](#cdaotabledef__canupdate) returns nonzero.  
  
 For related information, see the topic "Delete Method" in DAO Help.  
  
##  <a name="cdaotabledef__deleteindex"></a>  CDaoTableDef::DeleteIndex  
 Call this member function to delete an index in an underlying table.

void DeleteIndex(LPCTSTR lpszName);
void DeleteIndex(int nIndex); ```

Parameters

lpszName
A pointer to a string expression that is the name of an existing index.

nIndex
The array index of the index object in the database's zero-based TableDefs collection, for lookup by index.

Remarks

You can use this member function on a new object that hasn't been appended to the database or when CanUpdate returns nonzero.

For related information, see the topic "Delete Method" in DAO Help.

CDaoTableDef::GetAttributes

For a CDaoTableDef object, the return value specifies characteristics of the table represented by the CDaoTableDef object and can be a sum of these constants:

long GetAttributes();

Return Value

Returns a value that indicates one or more characteristics of a CDaoTableDef object.

Remarks

Constant	Description
dbAttachExclusive	For databases that use the Microsoft Jet database engine, indicates the table is an attached table opened for exclusive use.
dbAttachSavePWD	For databases that use the Microsoft Jet database engine, indicates that the user ID and password for the attached table are saved with the connection information.
dbSystemObject	Indicates the table is a system table provided by the Microsoft Jet database engine.
dbHiddenObject	Indicates the table is a hidden table provided by the Microsoft Jet database engine.
dbAttachedTable	Indicates the table is an attached table from a non-ODBC database, such as a Paradox database.
dbAttachedODBC	Indicates the table is an attached table from an ODBC database, such as Microsoft SQL Server.

A system table is a table created by the Microsoft Jet database engine to contain various internal information.

A hidden table is a table created for temporary use by the Microsoft Jet database engine.

For related information, see the topic "Attributes Property" in DAO Help.

CDaoTableDef::GetConnect

Call this member function to obtain the connection string for a data source.

CString GetConnect();

Return Value

A CString object containing the path and database type for the table.

Remarks

For a CDaoTableDef object that represents an attached table, the CString object consists of one or two parts (a database type specifier and a path to the database).

The path as shown in the table below is the full path for the directory containing the database files and must be preceded by the identifier "DATABASE=". In some cases (as with Microsoft Jet and Microsoft Excel databases), a specific filename is included in the database path argument.

The table in CDaoTableDef::SetConnect shows possible database types and their corresponding database specifiers and paths:

For Microsoft Jet database base tables, the specifier is a empty string ("").

If a password is required but not provided, the ODBC driver displays a login dialog box the first time a table is accessed and again if the connection is closed and reopened. If an attached table has the dbAttachSavePWD attribute, the login prompt will not appear when the table is reopened.

For related information, see the topic "Connect Property" in DAO Help.

CDaoTableDef::GetDateCreated

Call this function to determine the date and time the table underlying the CDaoTableDef object was created.

COleDateTime GetDateCreated();

Return Value

A value containing the date and time of the creation of the table underlying the CDaoTableDef object.

Remarks

The date and time settings are derived from the computer on which the base table was created or last updated. In a multiuser environment, users should get these settings directly from the file server to avoid discrepancies; that is, all clients should use a "standard" time source — perhaps from one server.

For related information, see the topic "DateCreated, LastUpdated Properties" in DAO Help.

CDaoTableDef::GetDateLastUpdated

Call this function to determine the date and time the table underlying the CDaoTableDef object was last updated.

COleDateTime GetDateLastUpdated();

Return Value

A value that contains the date and time the table underlying the CDaoTableDef object was last updated.

Remarks

For related information, see the topic "DateCreated, LastUpdated Properties" in DAO Help.

CDaoTableDef::GetFieldCount

Call this member function to retrieve the number of fields defined in the table.

short GetFieldCount();

Return Value

The number of fields in the table.

Remarks

If its value is 0, there are no objects in the collection.

For related information, see the topic "Count Property" in DAO Help.

CDaoTableDef::GetFieldInfo

Call this member function to obtain various kinds of information about a field defined in the tabledef.

void GetFieldInfo(
    int nIndex,  
    CDaoFieldInfo& fieldinfo,  
    DWORD dwInfoOptions = AFX_DAO_PRIMARY_INFO);

 
void GetFieldInfo(
    LPCTSTR lpszName,  
    CDaoFieldInfo& fieldinfo,  
    DWORD dwInfoOptions = AFX_DAO_PRIMARY_INFO);

Parameters

nIndex
The index of the field object in the table's zero-based Fields collection, for lookup by index.

fieldinfo
A reference to a CDaoFieldInfo structure.

dwInfoOptions
Options that specify which information about the field to retrieve. The available options are listed here along with what they cause the function to return:

AFX_DAO_PRIMARY_INFO (Default) Name, Type, Size, Attributes. Use this option for fastest performance.
AFX_DAO_SECONDARY_INFO Primary information, plus: Ordinal Position, Required, Allow Zero Length, Collating Order, Foreign Name, Source Field, Source Table
AFX_DAO_ALL_INFO Primary and secondary information, plus: Validation Rule, Validation Text, Default Value

lpszName
A pointer to the name of the field object, for lookup by name. The name is a string with up to 64 characters that uniquely names the field.

Remarks

One version of the function lets you look up a field by index. The other version lets you look up a field by name.

For a description of the information returned, see the CDaoFieldInfo structure. This structure has members that correspond to the items of information listed above in the description of dwInfoOptions. When you request information at one level, you get information for any prior levels as well.

For related information, see the topic "Attributes Property" in DAO Help.

CDaoTableDef::GetIndexCount

Call this member function to obtain the number of indexes for a table.

short GetIndexCount();

Return Value

The number of indexes for the table.

Remarks

If its value is 0, there are no indexes in the collection.

For related information, see the topic "Count Property" in DAO Help.

CDaoTableDef::GetIndexInfo

Call this member function to obtain various kinds of information about an index defined in the tabledef.

void GetIndexInfo(
    int nIndex,  
    CDaoIndexInfo& indexinfo,  
    DWORD dwInfoOptions = AFX_DAO_PRIMARY_INFO);

 
void GetIndexInfo(
    LPCTSTR lpszName,  
    CDaoIndexInfo& indexinfo,  
    DWORD dwInfoOptions = AFX_DAO_PRIMARY_INFO);

Parameters

nIndex
The numeric index of the Index object in the table's zero-based Indexes collection, for lookup by its position in the collection.

indexinfo
A reference to a CDaoIndexInfo structure.

dwInfoOptions
Options that specify which information about the index to retrieve. The available options are listed here along with what they cause the function to return:

AFX_DAO_PRIMARY_INFO Name, Field Info, Fields. Use this option for fastest performance.
AFX_DAO_SECONDARY_INFO Primary information, plus: Primary, Unique, Clustered, Ignore Nulls, Required, Foreign
AFX_DAO_ALL_INFO Primary and secondary information, plus: Distinct Count

lpszName
A pointer to the name of the index object, for lookup by name.

Remarks

One version of the function lets you look up an index by its position in the collection. The other version lets you look up an index by name.

For a description of the information returned, see the CDaoIndexInfo structure. This structure has members that correspond to the items of information listed above in the description of dwInfoOptions. When you request information at one level, you get information for any prior levels as well.

For related information, see the topic "Attributes Property" in DAO Help.

CDaoTableDef::GetName

Call this member function to obtain the user-defined name of the underlying table.

CString GetName();

Return Value

A user-defined name for a table.

Remarks

This name starts with a letter and can contain a maximum of 64 characters. It can include numbers and underscore characters but cannot include punctuation or spaces.

For related information, see the topic "Name Property" in DAO Help.

CDaoTableDef::GetRecordCount

Call this member function to find out how many records are in a CDaoTableDef object.

long GetRecordCount();

Return Value

The number of records accessed in a tabledef object.

Remarks

Calling GetRecordCount for a table-type CDaoTableDef object reflects the approximate number of records in the table and is affected immediately as table records are added and deleted. Rolled back transactions will appear as part of the record count until you call CDaoWorkSpace::CompactDatabase. A CDaoTableDef object with no records has a record count property setting of 0. When working with attached tables or ODBC databases, GetRecordCount always returns –1.

For related information, see the topic "RecordCount Property" in DAO Help.

CDaoTableDef::GetSourceTableName

Call this member function to retrieve the name of an attached table in a source database.

CString GetSourceTableName();

Return Value

A CString object that specifies the source name of an attached table, or an empty string if a native data table.

Remarks

An attached table is a table in another database linked to a Microsoft Jet database. Data for attached tables remains in the external database, where it can be manipulated by other applications.

For related information, see the topic "SourceTableName Property" in DAO Help.

CDaoTableDef::GetValidationRule

Call this member function to retrieve the validation rule for a tabledef.

CString GetValidationRule();

Return Value

A CString object that validates the data in a field as it is changed or added to a table.

Remarks

Validation rules are used in connection with update operations. If a tabledef contains a validation rule, updates to that tabledef must match predetermined criteria before the data is changed. If the change does not match the criteria, an exception containing the value of GetValidationText is thrown. For a CDaoTableDef object, this CString is read-only for an attached table and read/write for a base table.

For related information, see the topic "ValidationRule Property" in DAO Help.

CDaoTableDef::GetValidationText

Call this function to retrieve the string to display when a user enters data that does not match the validation rule.

CString GetValidationText();

Return Value

A CString object that specifies the text displayed if the user enters data that does not match the validation rule.

Remarks

For a CDaoTableDef object, this CString is read-only for an attached table and read/write for a base table.

For related information, see the topic "ValidationText Property" in DAO Help.

CDaoTableDef::IsOpen

Call this member function to determine whether the CDaoTableDef object is currently open.

BOOL IsOpen() const;

Return Value

Nonzero if the CDaoTableDef object is open; otherwise 0.

Remarks

CDaoTableDef::m_pDatabase

Contains a pointer to the CDaoDatabase object for this table.

Remarks

CDaoTableDef::m_pDAOTableDef

Contains a pointer to the OLE interface for the DAO tabledef object underlying the CDaoTableDef object.

Remarks

Use this pointer if you need to access the DAO interface directly.

CDaoTableDef::Open

Call this member function to open a tabledef previously saved in the database's TableDef's collection.

virtual void Open(LPCTSTR lpszName);

Parameters

lpszName
A pointer to a string that specifies a table name.

Remarks

CDaoTableDef::RefreshLink

Call this member function to update the connection information for an attached table.

void RefreshLink();

Remarks

You change the connection information for an attached table by calling SetConnect on the corresponding CDaoTableDef object and then using the RefreshLink member function to update the information. When you call RefreshLink, the attached table's properties are not changed.

To force the modified connect information to take effect, all open CDaoRecordset objects based on this tabledef must be closed.

For related information, see the topic "RefreshLink Method" in DAO Help.

CDaoTableDef::SetAttributes

Sets a value that indicates one or more characteristics of a CDaoTableDef object.

void SetAttributes(long lAttributes);

Parameters

lAttributes
Characteristics of the table represented by the CDaoTableDef object and can be a sum of these constants:

Constant	Description
dbAttachExclusive	For databases that use the Microsoft Jet database engine, indicates the table is an attached table opened for exclusive use.
dbAttachSavePWD	For databases that use the Microsoft Jet database engine, indicates that the user ID and password for the attached table are saved with the connection information.
dbSystemObject	Indicates the table is a system table provided by the Microsoft Jet database engine.
dbHiddenObject	Indicates the table is a hidden table provided by the Microsoft Jet database engine.

Remarks

When setting multiple attributes, you can combine them by summing the appropriate constants using the bitwise-OR operator. Setting dbAttachExclusive on a nonattached table produces an exception. Combining the following values also produce an exception:

dbAttachExclusive | dbAttachedODBC
dbAttachSavePWD | dbAttachedTable

For related information, see the topic "Attributes Property" in DAO Help.

CDaoTableDef::SetConnect

For a CDaoTableDef object that represents an attached table, the string object consists of one or two parts (a database type specifier and a path to the database).

void SetConnect(LPCTSTR lpszConnect);

Parameters

lpszConnect
A pointer to a string expression that specifies additional parameters to pass to ODBC or installable ISAM drivers.

Remarks

Note

Do not include whitespace around the equal sign in path statements of the form "DATABASE=drive:\\path". This will result in an exception being thrown and the connection failing.

The following table shows possible database types and their corresponding database specifiers and paths:

Database type	Specifier	Path
Database using the Jet database engine	"[ `database`];"	" `drive`:\\ path\\ filename.MDB"
dBASE III	"dBASE III;"	" `drive`:\\ path"
dBASE IV	"dBASE IV;"	" `drive`:\\ path"
dBASE 5	"dBASE 5.0;"	" `drive`:\\ path"
Paradox 3.x	"Paradox 3.x;"	" `drive`:\\ path"
Paradox 4.x	"Paradox 4.x;"	" `drive`:\\ path"
Paradox 5.x	"Paradox 5.x;"	" `drive`:\\ path"
Excel 3.0	"Excel 3.0;"	" `drive`:\\ path\\ filename.XLS"
Excel 4.0	"Excel 4.0;"	" `drive`:\\ path\\ filename.XLS"
Excel 5.0 or Excel 95	"Excel 5.0;"	" `drive`:\\ path\\ filename.XLS"
Excel 97	"Excel 8.0;"	" `drive`:\\ path\ filename.XLS"
HTML Import	"HTML Import;"	" `drive`:\\ path\ filename"
HTML Export	"HTML Export;"	" `drive`:\\ path"
Text	"Text;"	"drive:\\path"
ODBC	"ODBC; DATABASE= `database`; UID= user;PWD= password; DSN= datasourcename; LOGINTIMEOUT= seconds;" (This may not be a complete connection string for all servers; it is just an example. It is very important not to have spaces between the parameters.)	None
Exchange	"Exchange; MAPILEVEL= folderpath; [TABLETYPE={ 0 \| 1 };] [PROFILE= profile;] [PWD= password;] [DATABASE= `database`;]"	"drive:\\ path\\ filename.MDB"

Note

Btrieve is no longer supported as of DAO 3.5.

You must use a double backslash (\\) in the connection strings. If you have modified the properties of an existing connection using SetConnect, you must subsequently call RefreshLink. If you are initializing the connection properties using SetConnect, you need not call RefreshLink, but should you choose to do so, first append the tabledef.

If a password is required but not provided, the ODBC driver displays a login dialog box the first time a table is accessed and again if the connection is closed and reopened.

You can set the connection string for a CDaoTableDef object by providing a source argument to the Create member function. You can check the setting to determine the type, path, user ID, password, or ODBC data source of the database. For more information, see the documentation for the specific driver.

For related information, see the topic "Connect Property" in DAO Help.

CDaoTableDef::SetName

Call this member function to set a user-defined name for a table.

void SetName(LPCTSTR lpszName);

Parameters

lpszName
A pointer to a string expression that specifies a name for a table.

Remarks

The name must start with a letter and can contain a maximum of 64 characters. It can include numbers and underscore characters but cannot include punctuation or spaces.

For related information, see the topic "Name Property" in DAO Help.

CDaoTableDef::SetSourceTableName

Call this member function to specify the name of an attached table or the name of the base table on which the CDaoTableDef object is based, as it exists in the original source of the data.

void SetSourceTableName(LPCTSTR lpszSrcTableName);

Parameters

lpszSrcTableName
A pointer to a string expression that specifies a table name in the external database. For a base table, the setting is an empty string ("").

Remarks

You must then call RefreshLink. This property setting is empty for a base table and read/write for an attached table or an object not appended to a collection.

For related information, see the topic "SourceTableName Property" in DAO Help.

CDaoTableDef::SetValidationRule

Call this member function to set a validation rule for a tabledef.

void SetValidationRule(LPCTSTR lpszValidationRule);

Parameters

lpszValidationRule
A pointer to a string expression that validates an operation.

Remarks

Validation is supported only for databases that use the Microsoft Jet database engine. The expression cannot refer to user-defined functions, domain aggregate functions, SQL aggregate functions, or queries. A validation rule for a CDaoTableDef object can refer to multiple fields in that object.

For example, for fields named hire_date and termination_date, a validation rule might be:

   myTableDef.SetValidationRule(_T("termination_date > hire_date"));

For related information, see the topic "ValidationRule Property" in DAO Help.

CDaoTableDef::SetValidationText

Call this member function to set the exception text of a validation rule for a CDaoTableDef object with an underlying base table supported by the Microsoft Jet database engine.

void SetValidationText(LPCTSTR lpszValidationText);

Parameters

lpszValidationText
A pointer to a string expression that specifies the text displayed if entered data is invalid.

Remarks

You cannot set the validation text of an attached table.

For related information, see the topic "ValidationText Property" in DAO Help.

通过

CDaoTableDef Class

Syntax

Members

Public Constructors

Public Methods

Public Data Members

Remarks

To use tabledef objects either to work with an existing table or to create a new table

Inheritance Hierarchy

Requirements

CDaoTableDef::Append

Remarks

CDaoTableDef::CanUpdate

Return Value

Remarks

CDaoTableDef::CDaoTableDef

Parameters

Remarks

CDaoTableDef::Close

Remarks

CDaoTableDef::Create

Parameters

Remarks

CDaoTableDef::CreateField

Parameters

Remarks

CDaoTableDef::CreateIndex

Parameters

Remarks

CDaoTableDef::DeleteField

Parameters

Remarks

CDaoTableDef::GetAttributes

Return Value

Remarks

CDaoTableDef::GetConnect

Return Value

Remarks

CDaoTableDef::GetDateCreated

Return Value

Remarks

CDaoTableDef::GetDateLastUpdated

Return Value

Remarks

CDaoTableDef::GetFieldCount

Return Value

Remarks

CDaoTableDef::GetFieldInfo

Parameters

Remarks

CDaoTableDef::GetIndexCount

Return Value

Remarks

CDaoTableDef::GetIndexInfo

Parameters

Remarks

CDaoTableDef::GetName

Return Value

Remarks

CDaoTableDef::GetRecordCount

Return Value

Remarks

CDaoTableDef::GetSourceTableName

Return Value

Remarks

CDaoTableDef::GetValidationRule

Return Value

Remarks

CDaoTableDef::GetValidationText

Return Value

Remarks

CDaoTableDef::IsOpen

Return Value

Remarks

CDaoTableDef::m_pDatabase

Remarks

CDaoTableDef::m_pDAOTableDef

Remarks

CDaoTableDef::Open