GetSchema 参数解析

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SQL Anywhere 12.0.0»SQL Anywhere Server - Programming».NET application programming»SQL Anywhere .NET API reference»SAConnection class»GetSchema method

 

GetSchema(string, string[]) method

Returns schema information for the data source of this SAConnection object and, if specified, uses the specified string for the schema name and the specified string array for the restriction values.

 Visual Basic syntax

Public Overrides Function GetSchema(    ByVal collection As String,    ByVal restrictions As String()) As DataTable

 C# syntax

public override DataTable GetSchema(    string collection,    string[] restrictions)

 Returns

A DataTable that contains schema information.

 Remarks

These methods are used to query the database server for various metadata. Each type of metadata is given a collection name, which must be passed to receive that data. The default collection name is MetaDataCollections.

You can query the SQL Anywhere SQL Anywhere .NET Data Provider to determine the list of supported schema collections by calling the GetSchema method with no arguments, or with the schema collection name MetaDataCollections. This will return a DataTable with a list of the supported schema collections (CollectionName), the number of restrictions that they each support (NumberOfRestrictions), and the number of identifier parts that they use (NumberOfIdentifierParts).

CollectionMetadataColumnsReturns information on all columns in the database.DataSourceInformationReturns information about the database server.DataTypesReturns a list of supported data types.ForeignKeysReturns information on all foreign keys in the database.IndexColumnsReturns information on all index columns in the database.IndexesReturns information on all indexes in the database.MetaDataCollectionsReturns a list of all collection names.ProcedureParametersReturns information on all procedure parameters in the database.ProceduresReturns information on all procedures in the database.ReservedWordsReturns a list of reserved words used by SQL Anywhere.RestrictionsReturns information on restrictions used in GetSchema.TablesReturns information on all tables in the database.UserDefinedTypesReturns information on all user-defined data types in the database.UsersReturns information on all users in the database.ViewColumnsReturns information on all columns in views in the database.ViewsReturns information on all views in the database.

These collection names are also available as read-only properties in the SAMetaDataCollectionNames class.

The results returned can be filtered by specifying an array of restrictions in the call to GetSchema.

The restrictions available with each collection can be queried by calling:

GetSchema( "Restrictions" )

If the collection requires four restrictions, then the restrictions parameter must be either NULL, or a string with four values.

To filter on a particular restriction, place the string to filter by in its place in the array and leave any unused places NULL. For example, the Tables collection has three restrictions: Owner, Table, and TableType.

To filter the Table collection by table_name:

GetSchema( "Tables", new string[ ] { NULL, "my_table", NULL } )

This returns information on all tables named my_table.

GetSchema( "Tables", new string[ ] { "DBA", "my_table", NULL } )

This returns information on all tables named my_table owned by the user DBA.

The following is a summary of the columns returned by each collection. If the number of rows returned in a collection can be reduced by specifying a restriction on a column, the restriction name for that column is shown in parenthesis. The order in which restrictions are specified is the order in which they are presented in the lists below.

Columns collection

• table_schema (Owner)

• table_name (Table)

• column_name (Column)

• ordinal_position

• column_default

• is_nullable

• data_type

• precision

• scale

• column_size

DataSourceInformation collection

• CompositeIdentifierSeparatorPattern

• DataSourceProductName

• DataSourceProductVersion

• DataSourceProductVersionNormalized

• GroupByBehavior

• IdentifierPattern

• IdentifierCase

• OrderByColumnsInSelect

• ParameterMarkerFormat

• ParameterMarkerPattern

• ParameterNameMaxLength

• ParameterNamePattern

• QuotedIdentifierPattern

• QuotedIdentifierCase

• StatementSeparatorPattern

• StringLiteralPattern

• SupportedJoinOperators

DataTypes collection

• TypeName

• ProviderDbType

• ColumnSize

• CreateFormat

• CreateParameters

• DataType

• IsAutoIncrementable

• IsBestMatch

• IsCaseSensitive

• IsFixedLength

• IsFixedPrecisionScale

• IsLong

• IsNullable

• IsSearchable

• IsSearchableWithLike

• IsUnsigned

• MaximumScale

• MinimumScale

• IsConcurrencyType

• IsLiteralSupported

• LiteralPrefix

• LiteralSuffix

ForeignKeys collection

• table_schema (Owner)

• table_name (Table)

• column_name (Column)

IndexColumns collection

• table_schema (Owner)

• table_name (Table)

• index_name (Name)

• column_name (Column)

• order

Indexes collection

• table_schema (Owner)

• table_name (Table)

• index_name (Name)

• primary_key

• is_unique

MetaDataCollections collection

• CollectionName

• NumberOfRestrictions

• NumberOfIdentifierParts

ProcedureParameters collection

• procedure_schema (Owner)

• procedure_name (Name)

• parameter_name (Parameter)

• data_type

• parameter_type

• is_input

• is_output

Procedures collection

• procedure_schema (Owner)

• procedure_name (Name)

ReservedWords collection

• reserved_word

Restrictions collection

• CollectionName

• RestrictionName

• RestrictionDefault

• RestrictionNumber

Tables collection

• table_schema (Owner)

• table_name (Table)

• table_type (TableType)

UserDefinedTypes collection

• data_type

• default

• precision

• scale

Users collection

• user_name (UserName)

• resource_auth

• database_auth

• schedule_auth

• user_group

ViewColumns collection

• view_schema (Owner)

• view_name (Name)

• column_name (Column)

Views collection

• view_schema (Owner)

• view_name (Name)

 See also

• SAConnection class

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