ADO » Connection » OpenSchema
- Syntax:
- Set rsobject = connectionobject.OpenSchema (QueryType, Criteria, SchemaID)
- QueryType
- The mandatory QueryType parameter is one of the SchemaEnum constants that describes the type of schema to use. There are 41 types of these SchemaEnum values to choose from. However, OLE DB specifications only require that three of these possibilities be supported. They are, adSchemaColumns, adSchemaProviderTypes, and adSchemaTables. Further, the provider is not required by OLE DB to support the Constraint Columns values imposed by the optional Criteria parameter (discussed below) for these three schemas.
- Criteria
- The optional Criteria parameter is a variant composed of an array of query constraints for each of the values in the SchemaEnum constants. These are called Constraint Columns and they set limits to the results obtained using a schema query.
- SchemaID
- The SchemaID parameter is required if the QueryType parameter is set to the adSchemaProviderSpecific constant. This indicates that the query is a provider schema that is not defined by OLE DB specifications.
Returns descriptive schema information from the provider about the data source.
The OpenSchema method returns a read-only RecordSet object that contains schema
(which means self-descriptive) information about the data source.
For example, schema information can include the names of the tables, the names of the columns in the tables,
and the data type of each column.
There is one mandatory parameter and two optional parameters.
SchemaEnum Constants
| Constant | Value | Description |
| adSchemaColumns | 4 | Request column information |
| adSchemaProviderTypes | 22 | Request provider type information |
| adSchemaTables | 20 | Request table information |
SchemaEnum Constants and Constraint Columns Values
| Constant | Value | Description | Constraint Columns |
| adSchemaAsserts | 0 | Returns the assertions |
CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME |
| adSchemaCatalogs | 1 | Returns the catalog information | CATALOG_NAME |
| adSchemaCharacterSets | 2 | Returns the defined character set in the catalog |
CHARACTER_SET_CATALOG CHARACTER_SET_SCHEMA CHARACTER_SET_NAME |
| adSchemaCheckConstraints | 5 | Returns the defined check constraints in the catalog |
CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME |
| adSchemaCollations | 3 | Returns the defined character collations in the catalog |
COLLATION_CATALOG COLLATION_SCHEMA COLLATION_NAME |
| adSchemaColumnDomainUsage | 11 | Returns the columns that are domain dependent |
DOMAIN_CATALOG DOMAIN_SCHEMA DOMAIN_NAME COLUMN_NAME |
| adSchemaColumnPrivileges | 13 | Returns the column privilege information |
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME COLUMN_NAME GRANTOR GRANTEE |
| adSchemaColumns | 4 | Returns the columns information |
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME COLUMN_NAME |
| adSchemaConstraintColumnUsage | 6 | Returns the columns used by constraints |
COLUMN_NAME TABLE_CATALOG TABLE_SCHEMA TABLE_NAME |
| adSchemaConstraintTableUsage | 7 | Returns the tables used by constraints |
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME |
| adSchemaCubes | 32 | Returns info about the cubes used for multi-dimensional data |
CATALOG_NAME SCHEMA_NAME CUBE_NAME |
| adSchemaDBInfoKeywords | 30 | Return the keywords recognized by the provider | none |
| adSchemaDBInfoLiterals | 31 | Return the literals used in text commands by the provider | none |
| adSchemaDimensions | 33 | Returns info about the dimensions in a cube |
CATALOG_NAME SCHEMA_NAME CUBE_NAME DIMENSION_NAME DIMENSION_UNIQUE_NAME |
| adSchemaForeignKeys | 27 | Returns the foreign key column |
PK_TABLE_CATALOG PK_TABLE_SCHEMA PK_TABLE_NAME FK_TABLE_CATALOG FK_TABLE_SCHEMA FK_TABLE_NAME |
| adSchemaHierarchies | 34 | Returns hierarchy info for multi-dimensional data |
CATALOG_NAME SCHEMA_NAME CUBE_NAME DIMENSION_UNIQUE_NAME HIERARCHY_NAME HIERARCHY_UNIQUE_NAME |
| adSchemaIndexes | 12 | Returns the indexes defined in a catalog |
TABLE_CATALOG TABLE_SCHEMA INDEX_NAME TYPE TABLE_NAME |
| adSchemaKeyColumnUsage | 8 | Returns the defined key columns in the catalog |
COLUMN_NAME CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME TABLE_CATALOG TABLE_SCHEMA TABLE_NAME |
| adSchemaLevels | 35 | Returns info about the levels in multi-dimensional data |
CATALOG_NAME SCHEMA_NAME CUBE_NAME DIMENSION_UNIQUE_NAME HIERARCHY_UNIQUE_NAME LEVEL_NAME LEVEL_UNIQUE_NAME |
| adSchemaMeasures | 36 | Returns the measures for multi-dimensional data |
CATALOG_NAME SCHEMA_NAME CUBE_NAME MEASURE_NAME MEASURE_UNIQUE_NAME |
| adSchemaMembers | 38 | Returns the available members for multi-dimensional data |
CATALOG_NAME SCHEMA_NAME CUBE_NAME DIMENSION_UNIQUE_NAME HIERARCHY_UNIQUE_NAME LEVEL_UNIQUE_NAME LEVEL_NUMBER MEMBER_NAME MEMBER_UNIQUE_NAME MEMBER_CAPTION MEMBER_TYPE TREE OPERATOR |
| adSchemaPrimaryKeys | 28 | Returns the primary key columns |
PK_TABLE_CATALOG PK_TABLE_SCHEMA PK_TABLE_NAME |
| adSchemaProcedureColumns | 29 | Returns info on columns returned by stored procedures |
PROCEDURE_CATALOG PROCEDURE_SCHEMA PROCEDURE_NAME COLUMN_NAME |
| adSchemaProcedureParameters | 26 | Returns info on the parameters and return codes of stored procedures |
PROCEDURE_CATALOG PROCEDURE_SCHEMA PROCEDURE_NAME PARAMETER_NAME |
| adSchemaProcedures | 16 | Returns info on the stored procedures |
PROCEDURE_CATALOG PROCEDURE_SCHEMA PROCEDURE_NAME PROCEDURE_TYPE |
| adSchemaProperties | 37 | Returns info on the properties of each level of multi-dimensional data |
CATALOG_NAME SCHEMA_NAME CUBE_NAME DIMENSION_UNIQUE_NAME HIERARCHY_UNIQUE_NAME LEVEL_UNIQUE_NAME MEMBER_UNIQUE_NAME PROPERTY_TYPE PROPERTY_NAME |
| adSchemaProviderSpecific | -1 | For provider-specific, non-standard schema | provider specfic |
| adSchemaProviderTypes | 22 | Returns the provider-supported data types |
DATA_TYPE BEST_MATCH |
| adSchemaReferentialConstraints | 9 | Returns the defined referential constraints in the catalog |
CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME |
| adSchemaSchemata | 17 | Returns the schema owned by a user |
CATALOG_NAME SCHEMA_NAME SCHEMA_OWNER |
| adSchemaSQLLanguages | 18 | Returns the SQL language support info | none |
| adSchemaStatistics | 19 | Returns the defined statistics in a catalog |
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME |
| adSchemaTableConstraints | 10 | Returns the table contraints defined in the catalog |
CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME TABLE_CATALOG TABLE_SCHEMA TABLE_NAME CONSTRAINT_TYPE |
| adSchemaTablePrivileges | 14 | Returns the privileges on tables |
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME GRANTOR GRANTEE |
| adSchemaTables | 20 | Returns the tables in a catalog |
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME TABLE_TYPE |
| adSchemaTranslations | 21 | Returns the character set translation info |
TRANSLATION_CATALOG TRANSLATION_SCHEMA TRANSLATION_NAME |
| adSchemaTrustees | 39 | Not used | none |
| adSchemaUsagePrivileges | 15 | Returns the user privilege info |
OBJECT_CATALOG OBJECT_SCHEMA OBJECT_NAME OBJECT_TYPE GRANTOR GRANTEE |
| adSchemaViewColumnUsage | 24 | Returns the column usage for viewed tables |
VIEW_CATALOG VIEW_SCHEMA VIEW_NAME |
| adSchemaViews | 23 | Returns the views info from the catalog |
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME |
| adSchemaViewTableUsage | 25 | Returns the table usage for viewed tables |
VIEW_CATALOG VIEW_SCHEMA VIEW_NAME |
Examples
Code:
Set objRecordset = objConnection.OpenSchema(adSchemaTables)
See Also:
