OpenSchema 方法范例 该范例使用 OpenSchema 方法显示 Pubs 数据库内每个表的名称和类型。Public Sub OpenSchemaX() Dim cnn1 As ADODB.Connection Dim rstSchema As ADODB.Recordset Dim strCnn As String
Set cnn1 = New ADODB.Connection strCnn = "Provider=sqloledb;" & _ "Data Source=srv;Initial Catalog=pubs;User Id=sa;Password=; " cnn1.Open strCnn
End Sub该范例在 OpenSchema 方法的 Criteria 参数中指定 TABLE_TYPE 查询约束。因此,只返回在 Pubs 数据库中指定的 Views 的纲要信息。然后该范例显示这些表的名称和类型。Public Sub OpenSchemaX2() Dim cnn2 As ADODB.Connection Dim rstSchema As ADODB.Recordset Dim strCnn As String
Set cnn2 = New ADODB.Connection strCnn = "Provider=sqloledb;" & _ "Data Source=srv;Initial Catalog=pubs;User Id=sa;Password=; " cnn2.Open strCnn
以下程序有何错误 Set cnn1 = New ADODB.Connection cnn1.Open "Provider=sqloledb;Data Source=TANGZL;Initial Catalog=pubs;User Id=sa;Password=sa;"Set pk1 = cnn1.OpenSchema(adSchemaPrimaryKeys, Array(Empty, Empty, "product")) grid1.Clear grid1.Rows = pk1.RecordCount + 1 grid1.Cols = pk1.Fields.CountFor i = 0 To pk1.Fields.Count - 1 grid1.TextMatrix(0, i) = pk1.Fields(i).Name Next i pk1.MoveFirst For i = 0 To pk1.RecordCount - 1 For j = 0 To pk1.Fields.Count - 1 If Not IsNull(pk1.Fields(j).Value) Then grid1.TextMatrix(i + 1, j) = pk1.Fields(j).Value End If Next j pk1.MoveNext Next i错误提示: 下标越界 错误指向grid1.TextMatrix(0, i) = pk1.Fields(i).Name而下标看上去并无越界现象
从提供者获取数据库纲要信息。语法Set recordset = connection.OpenSchema (QueryType, Criteria, SchemaID)返回值返回包含纲要信息的 Recordset 对象。Recordset 将以只读、静态游标打开。参数QueryType 所要运行的纲要查询类型,可以为下列任意常量。Criteria 可选。每个 QueryType 选项的查询限制条件数组如下所列。QueryType 值 Criteria 值
adSchemaAsserts CONSTRAINT_CATALOG
CONSTRAINT_SCHEMA
CONSTRAINT_NAME
adSchemaCatalogs CATALOG_NAME
adSchemaCharacterSets CHARACTER_SET_CATALOG
CHARACTER_SET_SCHEMA
CHARACTER_SET_NAME
adSchemaCheckConstraints CONSTRAINT_CATALOG
CONSTRAINT_SCHEMA
CONSTRAINT_NAME
adSchemaCollations COLLATION_CATALOG
COLLATION_SCHEMA
COLLATION_NAME
adSchemaColumnDomainUsage DOMAIN_CATALOG
DOMAIN_SCHEMA
DOMAIN_NAME
COLUMN_NAME
adSchemaColumnPrivileges TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
COLUMN_NAME
GRANTOR
GRANTEE
adSchemaColumns TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
COLUMN_NAME
adSchemaConstraintColumnUsage TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
COLUMN_NAME
adSchemaConstraintTableUsage TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
adSchemaForeignKeys PK_TABLE_CATALOG
PK_TABLE_SCHEMA
PK_TABLE_NAME
FK_TABLE_CATALOG
FK_TABLE_SCHEMA
FK_TABLE_NAME
adSchemaIndexes TABLE_CATALOG
TABLE_SCHEMA
INDEX_NAME
TYPE
TABLE_NAME
adSchemaKeyColumnUsage CONSTRAINT_CATALOG
CONSTRAINT_SCHEMA
CONSTRAINT_NAME
TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
COLUMN_NAME
adSchemaPrimaryKeys PK_TABLE_CATALOG
PK_TABLE_SCHEMA
PK_TABLE_NAME
adSchemaProcedureColumns PROCEDURE_CATALOG
PROCEDURE_SCHEMA
PROCEDURE_NAME
COLUMN_NAME
adSchemaProcedureParameters PROCEDURE_CATALOG
PROCEDURE_SCHEMA
PROCEDURE_NAME
PARAMTER_NAME
adSchemaProcedures PROCEDURE_CATALOG
PROCEDURE_SCHEMA
PROCEDURE_NAME
PARAMTER_TYPE
adSchemaProviderSpecific 参见说明
adSchemaProviderTypes DATA_TYPE
BEST_MATCH
adSchemaReferentialConstraints CONSTRAINT_CATALOG
CONSTRAINT_SCHEMA
CONSTRAINT_NAME
adSchemaSchemata CATALOG_NAME
SCHEMA_NAME
SCHEMA_OWNER
adSchemaSQLLanguages <无>
adSchemaStatistics TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
adSchemaTableConstraints CONSTRAINT_CATALOG
CONSTRAINT_SCHEMA
CONSTRAINT_NAME
TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
CONSTRAINT_TYPE
adSchemaTablePrivileges TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
GRANTOR
GRANTEE
adSchemaTables TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
TABLE_TYPE
adSchemaTranslations TRANSLATION_CATALOG
TRANSLATION_SCHEMA
TRANSLATION_NAME
adSchemaUsagePrivileges OBJECT_CATALOG
OBJECT_SCHEMA
OBJECT_NAME
OBJECT_TYPE
GRANTOR
GRANTEE
adSchemaViewColumnUsage VIEW_CATALOG
VIEW_SCHEMA
VIEW_NAME
adSchemaViewTableUsage VIEW_CATALOG
VIEW_SCHEMA
VIEW_NAME
adSchemaViews TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
SchemaID OLE DB 规范没有定义提供者纲要查询的 GUID。如果 QueryType 设置为 adSchemaProviderSpecific,则需要该参数,否则不使用它。说明OpenSchema 方法返回与数据源有关的信息,如关于服务器上的表以及表中的列等信息。Criteria 参数是可用于限制纲要查询结果的值数组。每个纲要查询有它支持的不同参数集。实际纲要由 IDBSchemaRowset 接口下的 OLE DB 规范定义。ADO 中所支持的参数集已在上面列出。如果提供者定义未在上面列出的非标准纲要查询,则常量 adSchemaProviderSpecific 将用于 QueryType 参数。在使用该常量时需要 SchemaID 参数传递纲要查询的 GUID 以用于执行。如果 QueryType 设置为 adSchemaProviderSpecific 但是没有提供 SchemaID,将导致错误。提供者不需要支持所有的 OLE DB 标准纲要查询,只有 adSchemaTables、adSchemaColumns 和 adSchemaProviderTypes 是 OLE DB 规范所需要的。但是对于这些纲要查询,提供者不需要支持上面列出的 Criteria 条件约束。Remote Data Service 用法 OpenSchema 方法在客户端 Connection 对象上无效。
该范例使用 OpenSchema 方法显示 Pubs 数据库内每个表的名称和类型。Public Sub OpenSchemaX() Dim cnn1 As ADODB.Connection
Dim rstSchema As ADODB.Recordset
Dim strCnn As String
Set cnn1 = New ADODB.Connection
strCnn = "Provider=sqloledb;" & _
"Data Source=srv;Initial Catalog=pubs;User Id=sa;Password=; "
cnn1.Open strCnn
Set rstSchema = cnn1.OpenSchema(adSchemaTables)
Do Until rstSchema.EOF
Debug.Print "Table name: " & _
rstSchema!TABLE_NAME & vbCr & _
"Table type: " & rstSchema!TABLE_TYPE & vbCr
rstSchema.MoveNext
Loop
rstSchema.Close
cnn1.Close
End Sub该范例在 OpenSchema 方法的 Criteria 参数中指定 TABLE_TYPE 查询约束。因此,只返回在 Pubs 数据库中指定的 Views 的纲要信息。然后该范例显示这些表的名称和类型。Public Sub OpenSchemaX2() Dim cnn2 As ADODB.Connection
Dim rstSchema As ADODB.Recordset
Dim strCnn As String
Set cnn2 = New ADODB.Connection
strCnn = "Provider=sqloledb;" & _
"Data Source=srv;Initial Catalog=pubs;User Id=sa;Password=; "
cnn2.Open strCnn
Set rstSchema = cnn2.OpenSchema(adSchemaTables, Array(Empty, Empty, Empty, "VIEW")) Do Until rstSchema.EOF
Debug.Print "Table name: " & _
rstSchema!TABLE_NAME & vbCr & _
"Table type: " & rstSchema!TABLE_TYPE & vbCr
rstSchema.MoveNext
Loop
rstSchema.Close
cnn2.Close
End Sub
Set cnn1 = New ADODB.Connection
cnn1.Open "Provider=sqloledb;Data Source=TANGZL;Initial Catalog=pubs;User Id=sa;Password=sa;"Set pk1 = cnn1.OpenSchema(adSchemaPrimaryKeys, Array(Empty, Empty, "product"))
grid1.Clear
grid1.Rows = pk1.RecordCount + 1
grid1.Cols = pk1.Fields.CountFor i = 0 To pk1.Fields.Count - 1
grid1.TextMatrix(0, i) = pk1.Fields(i).Name
Next i
pk1.MoveFirst
For i = 0 To pk1.RecordCount - 1
For j = 0 To pk1.Fields.Count - 1
If Not IsNull(pk1.Fields(j).Value) Then
grid1.TextMatrix(i + 1, j) = pk1.Fields(j).Value
End If
Next j
pk1.MoveNext
Next i错误提示:
下标越界
错误指向grid1.TextMatrix(0, i) = pk1.Fields(i).Name而下标看上去并无越界现象