SqlConnection.GetSchema 方法
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
返回此 SqlConnection 的数据源的架构信息。
重载
| GetSchema() |
返回此 SqlConnection 的数据源的架构信息。 有关架构的详细信息，请参阅 SQL Server 架构集合。 |
| GetSchema(String) |
通过使用架构名称的指定字符串，返回此 SqlConnection 的数据源的架构信息。 |
| GetSchema(String, String[]) |
通过使用指定字符串作为架构名称，指定字符串数组作为限制值，返回此 SqlConnection 的数据源的架构信息。 |
注解
如果尝试检索多个版本控制存储过程的架构信息，则仅返回最新存储过程的架构。
GetSchema()
返回此 SqlConnection 的数据源的架构信息。 有关架构的详细信息，请参阅 SQL Server 架构集合。
public:
override System::Data::DataTable ^ GetSchema();public override System.Data.DataTable GetSchema ();override this.GetSchema : unit -> System.Data.DataTablePublic Overrides Function GetSchema () As DataTable返回
一个包含架构信息的 DataTable。
另请参阅
适用于
GetSchema(String)
通过使用架构名称的指定字符串，返回此 SqlConnection 的数据源的架构信息。
public:
override System::Data::DataTable ^ GetSchema(System::String ^ collectionName);public override System.Data.DataTable GetSchema (string collectionName);override this.GetSchema : string -> System.Data.DataTablePublic Overrides Function GetSchema (collectionName As String) As DataTable参数
- collectionName
- String
指定要返回的架构的名称。
返回
一个包含架构信息的 DataTable。
例外
将 collectionName 指定为 null。
注解
可能需要数据库、表或列的架构信息。 此示例：
使用 GetSchema 获取架构信息。
使用架构限制获取指定信息。
获取数据库、表和某些列的架构信息。
在运行示例之前，需要使用以下 Transact-SQL 创建示例数据库：
USE [master]
GO
CREATE DATABASE [MySchool]
GO
USE [MySchool]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Course]([CourseID] [nvarchar](10) NOT NULL,
[Year] [smallint] NOT NULL,
[Title] [nvarchar](100) NOT NULL,
[Credits] [int] NOT NULL,
[DepartmentID] [int] NOT NULL,
CONSTRAINT [PK_Course] PRIMARY KEY CLUSTERED
(
[CourseID] ASC,
[Year] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]) ON [PRIMARY]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Department]([DepartmentID] [int] IDENTITY(1,1) NOT NULL,
[Name] [nvarchar](50) NOT NULL,
[Budget] [money] NOT NULL,
[StartDate] [datetime] NOT NULL,
[Administrator] [int] NULL,
CONSTRAINT [PK_Department] PRIMARY KEY CLUSTERED
(
[DepartmentID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]) ON [PRIMARY]
GO
INSERT [dbo].[Course] ([CourseID], [Year], [Title], [Credits], [DepartmentID]) VALUES (N'C1045', 2012, N'Calculus', 4, 7)
INSERT [dbo].[Course] ([CourseID], [Year], [Title], [Credits], [DepartmentID]) VALUES (N'C1061', 2012, N'Physics', 4, 1)
INSERT [dbo].[Course] ([CourseID], [Year], [Title], [Credits], [DepartmentID]) VALUES (N'C2021', 2012, N'Composition', 3, 2)
INSERT [dbo].[Course] ([CourseID], [Year], [Title], [Credits], [DepartmentID]) VALUES (N'C2042', 2012, N'Literature', 4, 2)
SET IDENTITY_INSERT [dbo].[Department] ON
INSERT [dbo].[Department] ([DepartmentID], [Name], [Budget], [StartDate], [Administrator]) VALUES (1, N'Engineering', 350000.0000, CAST(0x0000999C00000000 AS DateTime), 2)
INSERT [dbo].[Department] ([DepartmentID], [Name], [Budget], [StartDate], [Administrator]) VALUES (2, N'English', 120000.0000, CAST(0x0000999C00000000 AS DateTime), 6)
INSERT [dbo].[Department] ([DepartmentID], [Name], [Budget], [StartDate], [Administrator]) VALUES (4, N'Economics', 200000.0000, CAST(0x0000999C00000000 AS DateTime), 4)
INSERT [dbo].[Department] ([DepartmentID], [Name], [Budget], [StartDate], [Administrator]) VALUES (7, N'Mathematics', 250024.0000, CAST(0x0000999C00000000 AS DateTime), 3)
SET IDENTITY_INSERT [dbo].[Department] OFF
ALTER TABLE [dbo].[Course] WITH CHECK ADD CONSTRAINT [FK_Course_Department] FOREIGN KEY([DepartmentID])
REFERENCES [dbo].[Department] ([DepartmentID])
GO
ALTER TABLE [dbo].[Course] CHECK CONSTRAINT [FK_Course_Department]
GO
using System;
using System.Data;
using System.Data.SqlClient;
class Program {
static void Main(string[] args) {
using (SqlConnection conn = new SqlConnection("Data Source=(local);Initial Catalog=MySchool;Integrated Security=True;Asynchronous Processing=true;")) {
conn.Open();
// Get the Meta Data for Supported Schema Collections
DataTable metaDataTable = conn.GetSchema("MetaDataCollections");
Console.WriteLine("Meta Data for Supported Schema Collections:");
ShowDataTable(metaDataTable, 25);
Console.WriteLine();
// Get the schema information of Databases in your instance
DataTable databasesSchemaTable = conn.GetSchema("Databases");
Console.WriteLine("Schema Information of Databases:");
ShowDataTable(databasesSchemaTable, 25);
Console.WriteLine();
// First, get schema information of all the tables in current database;
DataTable allTablesSchemaTable = conn.GetSchema("Tables");
Console.WriteLine("Schema Information of All Tables:");
ShowDataTable(allTablesSchemaTable, 20);
Console.WriteLine();
// You can specify the Catalog, Schema, Table Name, Table Type to get
// the specified table(s).
// You can use four restrictions for Table, so you should create a 4 members array.
String[] tableRestrictions = new String[4];
// For the array, 0-member represents Catalog; 1-member represents Schema;
// 2-member represents Table Name; 3-member represents Table Type.
// Now we specify the Table Name of the table what we want to get schema information.
tableRestrictions[2] = "Course";
DataTable courseTableSchemaTable = conn.GetSchema("Tables", tableRestrictions);
Console.WriteLine("Schema Information of Course Tables:");
ShowDataTable(courseTableSchemaTable, 20);
Console.WriteLine();
// First, get schema information of all the columns in current database.
DataTable allColumnsSchemaTable = conn.GetSchema("Columns");
Console.WriteLine("Schema Information of All Columns:");
ShowColumns(allColumnsSchemaTable);
Console.WriteLine();
// You can specify the Catalog, Schema, Table Name, Column Name to get the specified column(s).
// You can use four restrictions for Column, so you should create a 4 members array.
String[] columnRestrictions = new String[4];
// For the array, 0-member represents Catalog; 1-member represents Schema;
// 2-member represents Table Name; 3-member represents Column Name.
// Now we specify the Table_Name and Column_Name of the columns what we want to get schema information.
columnRestrictions[2] = "Course";
columnRestrictions[3] = "DepartmentID";
DataTable departmentIDSchemaTable = conn.GetSchema("Columns", columnRestrictions);
Console.WriteLine("Schema Information of DepartmentID Column in Course Table:");
ShowColumns(departmentIDSchemaTable);
Console.WriteLine();
// First, get schema information of all the IndexColumns in current database
DataTable allIndexColumnsSchemaTable = conn.GetSchema("IndexColumns");
Console.WriteLine("Schema Information of All IndexColumns:");
ShowIndexColumns(allIndexColumnsSchemaTable);
Console.WriteLine();
// You can specify the Catalog, Schema, Table Name, Constraint Name, Column Name to
// get the specified column(s).
// You can use five restrictions for Column, so you should create a 5 members array.
String[] indexColumnsRestrictions = new String[5];
// For the array, 0-member represents Catalog; 1-member represents Schema;
// 2-member represents Table Name; 3-member represents Constraint Name;4-member represents Column Name.
// Now we specify the Table_Name and Column_Name of the columns what we want to get schema information.
indexColumnsRestrictions[2] = "Course";
indexColumnsRestrictions[4] = "CourseID";
DataTable courseIdIndexSchemaTable = conn.GetSchema("IndexColumns", indexColumnsRestrictions);
Console.WriteLine("Index Schema Information of CourseID Column in Course Table:");
ShowIndexColumns(courseIdIndexSchemaTable);
Console.WriteLine();
}
Console.WriteLine("Please press any key to exit...");
Console.ReadKey();
}
private static void ShowDataTable(DataTable table, Int32 length) {
foreach (DataColumn col in table.Columns) {
Console.Write("{0,-" + length + "}", col.ColumnName);
}
Console.WriteLine();
foreach (DataRow row in table.Rows) {
foreach (DataColumn col in table.Columns) {
if (col.DataType.Equals(typeof(DateTime)))
Console.Write("{0,-" + length + ":d}", row[col]);
else if (col.DataType.Equals(typeof(Decimal)))
Console.Write("{0,-" + length + ":C}", row[col]);
else
Console.Write("{0,-" + length + "}", row[col]);
}
Console.WriteLine();
}
}
private static void ShowDataTable(DataTable table) {
ShowDataTable(table, 14);
}
private static void ShowColumns(DataTable columnsTable) {
var selectedRows = from info in columnsTable.AsEnumerable()
select new {
TableCatalog = info["TABLE_CATALOG"],
TableSchema = info["TABLE_SCHEMA"],
TableName = info["TABLE_NAME"],
ColumnName = info["COLUMN_NAME"],
DataType = info["DATA_TYPE"]
};
Console.WriteLine("{0,-15}{1,-15}{2,-15}{3,-15}{4,-15}", "TableCatalog", "TABLE_SCHEMA",
"TABLE_NAME", "COLUMN_NAME", "DATA_TYPE");
foreach (var row in selectedRows) {
Console.WriteLine("{0,-15}{1,-15}{2,-15}{3,-15}{4,-15}", row.TableCatalog,
row.TableSchema, row.TableName, row.ColumnName, row.DataType);
}
}
private static void ShowIndexColumns(DataTable indexColumnsTable) {
var selectedRows = from info in indexColumnsTable.AsEnumerable()
select new {
TableSchema = info["table_schema"],
TableName = info["table_name"],
ColumnName = info["column_name"],
ConstraintSchema = info["constraint_schema"],
ConstraintName = info["constraint_name"],
KeyType = info["KeyType"]
};
Console.WriteLine("{0,-14}{1,-11}{2,-14}{3,-18}{4,-16}{5,-8}", "table_schema", "table_name", "column_name", "constraint_schema", "constraint_name", "KeyType");
foreach (var row in selectedRows) {
Console.WriteLine("{0,-14}{1,-11}{2,-14}{3,-18}{4,-16}{5,-8}", row.TableSchema,
row.TableName, row.ColumnName, row.ConstraintSchema, row.ConstraintName, row.KeyType);
}
}
}
另请参阅
适用于
GetSchema(String, String[])
通过使用指定字符串作为架构名称，指定字符串数组作为限制值，返回此 SqlConnection 的数据源的架构信息。
public:
override System::Data::DataTable ^ GetSchema(System::String ^ collectionName, cli::array <System::String ^> ^ restrictionValues);public override System.Data.DataTable GetSchema (string collectionName, string[] restrictionValues);override this.GetSchema : string * string[] -> System.Data.DataTablePublic Overrides Function GetSchema (collectionName As String, restrictionValues As String()) As DataTable参数
- collectionName
- String
指定要返回的架构的名称。
- restrictionValues
- String[]
请求的架构的一组限制值。
返回
一个包含架构信息的 DataTable。
例外
将 collectionName 指定为 null。
注解
参数 restrictionValues 可以提供 n 个深度的值，这些值由特定集合的限制集合指定。 若要设置给定限制的值，而不设置其他限制的值，需要将上述限制 null 设置为 ，然后为要为其指定值的限制放入适当的值。
“Tables”集合就是一个示例。 如果“Tables”集合有三个限制（数据库、所有者和表名称），并且只想取回与所有者“Carl”关联的表，则需要传入以下值：null、“Carl”。 如果未传入限制值，则默认值将用于该限制。 这与传入 null的映射相同，这不同于为参数值传入空字符串。 在这种情况下，空字符串 (“”) 被视为指定参数的值。
有关演示 的 GetSchema代码示例，请参阅 GetSchema。
