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How do I introspectively browse SQL Server?

I have a server with a vendor application that is highly database dependent. I need to make some minor changes to the data in several tables in the database automatically. Just INSERT and UPDATE, nothing out of the ordinary. Suppliers who are suppliers, I can never be absolutely sure when they change the database schema during the upgrade.

To this end, how can I ask the SQL server in some scenarios: “Hey, does this table still exist? Yes, cool, good, but does it have this column? What type and size of data is it for?” Is it null? "Could you give me a list of tables? In this table, could you give me a list of columns? Do you have primary keys?" I don’t need to do this for the whole schema, only part of it, just a quick check of the database before I start with it.

We currently have Microsoft SQL Server 2005, but it can easily upgrade to Microsoft SQL Server 2008. I probably do not use the correct terminology when searching. I know that ORM is not only too much overhead for this kind of thing, but also that I have no chance to pass it on to my colleagues.

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3 answers

Run the query as shown below, from it you can see:

  • schema name
  • table / view name
  • table type (for example: SYSTEM_TABLE, VIEW, SQL_TABLE_VALUED_FUNCTION, USER_TABLE, SQL_INLINE_TABLE_VALUED_FUNCTION, INTERNAL_TABLE)
  • column name
  • column data type (including length, precision, etc.)
  • validity of empty
  • the position of this column is basically the key
  • full primary key, all PK columns are merged together if this column is part of PK
  • identifier (seed, increment and current value)
  • definition of check constraint
  • calculation column definition

Requires running SQL Server 2005+:

--optional, remove comments on WHERE to use these
--DECLARE @SchemaNameSearch   sysname
--       ,@TableNameSearch    sysname
--       ,@ColumnNameSearch   sysname
--SELECT @SchemaNameSearch  ='YourSchemaName'
--      ,@TableNameSearch   ='YourTableName'
--      ,@ColumnNameSearch  ='YourColumnName'

SELECT
    sh.name+'.'+o.name AS ObjectName
        ,o.type_desc AS ObjectType
        ,s.name as ColumnName
        ,CASE
             WHEN t.name IN ('char','varchar') THEN t.name+'('+CASE WHEN s.max_length<0 then 'MAX' ELSE CONVERT(varchar(10),s.max_length) END+')'
             WHEN t.name IN ('nvarchar','nchar') THEN t.name+'('+CASE WHEN s.max_length<0 then 'MAX' ELSE CONVERT(varchar(10),s.max_length/2) END+')'
             WHEN t.name IN ('numeric') THEN t.name+'('+CONVERT(varchar(10),s.precision)+','+CONVERT(varchar(10),s.scale)+')'
             ELSE t.name
         END AS DataType

        ,CASE
             WHEN s.is_nullable=1 THEN 'NULL'
            ELSE 'NOT NULL'
        END AS Nullable
        ,xc.key_ordinal AS PK_Position
        ,CASE
             WHEN xc.key_ordinal IS NOT NULL THEN All_PKs.PrimaryKey
             ELSE NULL
         END AS PK
        ,CASE
             WHEN ic.column_id IS NULL THEN ''
             ELSE ' identity('+ISNULL(CONVERT(varchar(10),ic.seed_value),'')+','+ISNULL(CONVERT(varchar(10),ic.increment_value),'')+')='+ISNULL(CONVERT(varchar(10),ic.last_value),'null')
         END
        +CASE
             WHEN sc.column_id IS NULL THEN ''
             ELSE ' computed('+ISNULL(sc.definition,'')+')'
         END
        +CASE
             WHEN cc.object_id IS NULL THEN ''
             ELSE ' check('+ISNULL(cc.definition,'')+')'
         END
            AS MiscInfo
    FROM sys.objects                           o
        INNER JOIN sys.schemas                sh on o.schema_id=sh.schema_id
        INNER JOIN sys.columns                 s ON o.object_id=s.object_id
        INNER JOIN sys.types                   t ON s.system_type_id=t.system_type_id and t.is_user_defined=0
        LEFT OUTER JOIN sys.identity_columns  ic ON s.object_id=ic.object_id AND s.column_id=ic.column_id
        LEFT OUTER JOIN sys.computed_columns  sc ON s.object_id=sc.object_id AND s.column_id=sc.column_id
        LEFT OUTER JOIN sys.check_constraints cc ON s.object_id=cc.parent_object_id AND s.column_id=cc.parent_column_id
        LEFT OUTER JOIN sys.indexes            x ON o.object_id=x.object_id AND x.is_primary_key=1
        LEFT OUTER JOIN sys.index_columns     xc ON o.object_id=xc.object_id AND x.index_id=xc.index_id AND s.column_id=xc.column_id
        LEFT OUTER JOIN (SELECT --build the concatenated PK here
                             oo.object_id
                                  ,STUFF(
                                             (
                                              SELECT 
                                                   ', '+s.Name
                                                  FROM sys.objects                           o
                                                      LEFT OUTER JOIN sys.indexes            x ON o.object_id=x.object_id AND x.is_primary_key=1
                                                      LEFT OUTER JOIN sys.index_columns     xc ON o.object_id=xc.object_id AND x.index_id=xc.index_id 
                                                      LEFT OUTER JOIN sys.columns            s ON o.object_id=s.object_id AND s.column_id=xc.column_id
                                                 WHERE oo.object_id=o.object_id AND xc.column_id IS NOT NULL
                                                 ORDER BY o.object_ID,xc.key_ordinal
                                                 FOR XML PATH('') 
                                             )
                                            ,1,2, ''
                                        ) AS PrimaryKey
                               FROM sys.objects  oo
                               --
                               --REMOVE comments to filter the query
                               --WHERE oo.Name=@TableNameSearch 
                               --
                        )All_PKs ON o.object_id=All_PKs.object_id
    --
    --REMOVE comments to filter the query
    --WHERE sh.name =@SchemaNameSearch
    --    AND o.Name=@TableNameSearch 
    --    AND s.name=@ColumnNameSearch
    --
    ORDER BY sh.name+'.'+o.name,s.column_id

WHERE //.

, :

create this log table first:

CREATE TABLE YourLogTable (EventID int not null identity(1,1), EventDateTime datetime null, EventDescription  varchar(MAX) null)

USE [TheDatabase]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER [YourDatabaseTrigger]
ON DATABASE
FOR DDL_DATABASE_LEVEL_EVENTS --DDL_TABLE_EVENTS    --DDL_EVENTS
AS

DECLARE @EventData      xml
DECLARE @Message        varchar(1000)
SET @EventData=EVENTDATA()

INSERT INTO YourLogTable 
    (EventDateTime,EventDescription) 
    VALUES (GETDATE(),--SUSER_NAME()
                     --+'; '+@EventData.value('(/EVENT_INSTANCE/ObjectType)[1]', 'varchar(500)')
                     --+'; '+@EventData.value('(/EVENT_INSTANCE/ObjectName)[1]', 'varchar(500)')
                     --+'; '+@EventData.value('(/EVENT_INSTANCE/TSQLCommand/CommandText)[1]','nvarchar(8000)')
                     CONVERT(varchar(max),@EventData)
           )
RETURN

GO
SET ANSI_NULLS OFF
GO
SET QUOTED_IDENTIFIER OFF
GO
ENABLE TRIGGER [YourDatabaseTrigger] ON DATABASE

, .

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To do this through SQL, use the INFORMATION_SCHEMA views.

To do this with code, look at SQL Server Management Objects (SMOs):

http://msdn.microsoft.com/en-us/library/ms162169.aspx

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