SQL Server CREATE TABLE add primary key Add column common SQL statement

--Delete primary Key Alter TableTable nameDrop constraintPRIMARY Key Name--Add primary Key Alter TableTable nameAdd constraintPrimary Key NamePrimary Key(field name 1, field Name 2 ...)--to add a primary key for a nonclustered index Alter TableTable nameAdd constraintPrimary Key NamePrimary Key nonclustered(field name 1, field Name 2 ...) New table:Create Table [Table name]  (  [AutoNumber field] int IDENTITY(1,1)PRIMARY KEY ,  [Field 1] NVarChar( -)default\'default value \' NULL ,  [Field 2] ntext NULL ,  [Field 3] datetime,  [Field 4]  Money NULL ,  [Field 5] int default 0,  [Field 6] Decimal( A,4)default 0,  [Field 7] Image NULL,) to delete the table:Drop Table [Table name]Delete all tables:DECLARECuritemsCURSOR  for Select [name]  fromsysobjectswhereXtype='U'  for READ  only OPENCuritemsDECLARE @n  NVARCHAR( -),@m NVARCHAR( -) FETCH  fromCuritems into @n  while @ @FETCH_STATUS=0 BEGIN  Set @m=@n     exec('Drop Table' + @m) FETCH NEXT  fromCuritems into  @n END CLOSECuritemsdeallocatecuritems inserting data:INSERT  into [Table name](Field 1, Field 2)VALUES( -,\'51windows.net\') Delete data:DELETE  from [Table name] WHERE [Field name]> -Update Data:UPDATE [Table name] SET [Field 1] =  $,[Field 2] =\'51windows.net\' WHERE [Field Three] =\'haiwa\'New fields:ALTER TABLE [Table name] ADD [Field name] NVARCHAR( -)NULLTo delete a field:ALTER TABLE [Table name] DROP COLUMN [Field name]To Modify a field:ALTER TABLE [Table name] ALTER COLUMN [Field name] NVARCHAR( -)NULLRename table: (Access renames the table, refer to the article: Renaming a table in an Access database) sp_rename \'table name \', \'new table name \', \'object\'new constraint:ALTER TABLE [Table name] ADD CONSTRAINTConstraint nameCHECK([constraint fields] <=\'2000-1-1\') to delete the constraint:ALTER TABLE [Table name] DROP CONSTRAINTconstraint name new default valueALTER TABLE [Table name] ADD CONSTRAINTDefault Value NameDEFAULT\'51windows.net\'  for [Field name]Delete default valuesALTER TABLE [Table name] DROP CONSTRAINTDefault Value name delete logs from SQL Server, reducing database file sizeDump TransactionDatabase name withno_logBackup LogDatabase name withno_logDBCCshrinkdatabase (database name)execsp_dboption \'database name \', \'autoshrink\', \'true\'\\\'Add field General function Sub AddColumn (tablename,columnname,columntype) Conn.execute (\ "Alter Table \" &tablename&\ "add \" &columnname&\ "\" &columntype&\ "\") End sub\\\'Change the field general function Sub Modcolumn (tablename,columnname,columntype) Conn.Execute(\"Alter Table\"&TableName&\"Alter Column\"&ColumnName&\" \"&ColumnType&\"\")  Endsub\\\'Check if the table exists sql=\ "SELECT COUNT (*) as Dida from sysobjects where id = object_id (n\' [owner].[Table name]\') and OBJECTPROPERTY (ID, n\'Isusertable\') = 1\ "set Rs=conn.execute (SQL) Response.Write rs (\" Dida\ ") \'returns a numeric value, 0 for no, 1 for existence of a judgment table:Select *  fromsysobjectswhereId= object_id(n\'[dbo]. [Tablename]\') and ObjectProperty(ID, n\'isusertable\')= 1structure of a tableSelect *  fromsyscolumnswhereId= object_id(n\'[dbo]. [Your table name is]\') and ObjectProperty(ID, n\'isusertable\')= 1to modify the table prefix:ALTER SCHEMAdbo TRANSFER prename.tablename; If table 2 already exists, add the records in table 1 to the statement in Table 2:Insert    intoTable 2 (Field 1, Field 2,...)SelectField 1, Field 2,.. fromTable 2where   ... If Table 2 does not exist, table 2 is automatically generated with the following statement, with the same type of field as Table 1:SelectField 1, Field 2,.. intoTable 2 fromTable 1where...

SQL Server CREATE TABLE add primary key Add column common SQL statement