实例讲解Oracle到SQL Server主键的迁移

由于项目需要要将以前Oracle的数据库转化为SQL Server,今天利用SQL Server的DTD进行数据库的迁移，但导入以后发现只导入了表结构和数据，而表的一些主键约束都没导过来，感觉很郁闷，而手头又没有好的迁移工具，如Erwin,所以动手写了个小工具，基本实现了主键的转移，主要代码如下：

主要控件：

ADOConnOrcale: TADOConnection; //连接Oracle

ADOConnSQLServer: TADOConnection; //连接SQL Server

O1: TADOQuery; //连接Oracle

S1: TADOQuery; //连接SQL Server

S2: TADOQuery; //连接SQL Server

ProgressBar1: TProgressBar; //进度条

Memo1: TMemo; //显示出错信息

EdtServer: TEdit; //服务器

EdtDataBase: TEdit; //数据库名称

EdtUser: TEdit; //用户名

EdtPass: TEdit; //口令

Button1: TButton; //执行按钮

//常量

const

ORAConnStr='Provider=MSDAORA.1;Data Source=%S;User ID=%S;Password=%S;Persist Security Info=True';

SQLConnStr='Provider=SQLOLEDB.1;Data Source=%S;Initial Catalog=%S;User ID=%S;Password=%S;Persist Security Info=False';

在执行前先进行Oracle和SQL Server数据库的连接。

连接Oracle:

ADOConnOrcale.ConnectionString :=Format(ORAConnStr,[trim(EdtDataBase.Text),

trim(EdtUser.Text),trim(EdtPass.Text)]);

try

ADOConnOrcale.Open;

MsgBox('Oracle数据库连接成功！');

Except

MsgBox('Oracle数据库连接失败！');

end;

连接SQL Server:

ADOConnSQLServer.ConnectionString :=Format(SQLConnStr,[trim(EdtServer.Text),

trim(EdtDataBase.Text),trim(EdtUser.Text),trim(EdtPass.Text)]);

try

ADOConnSQLServer.Open;

MsgBox('SQL Server数据库连接成功！')

except

MsgBox('SQL Server数据库连接失败！');

end;

主要执行代码，比较乱，没有整理，不过实现功能就行了。

procedure TForm1.Button1Click(Sender: TObject);

var

i:Integer;

FieldN, tableN, fieldM,aa:String;

begin

if Not ADOConnOrcale.Connected then

begin

MsgBox('请先连接Oracle数据库！');

exit;

end;

if not ADOConnSQLServer.Connected then

begin

MsgBox('请先连接SQL Server数据库！');

exit;

end;

Screen.Cursor :=crHourGlass;

try

o1.Close;

O1.SQL.Clear;

//取oracle表用户budget的所有主键约束信息

o1.SQL.Text :=' select a.CONSTRAINT_NAME,a.CONSTRAINT_TYPE,a.TABLE_NAME, b.COLUMN_NAME,b.position '+

' from USER_CONSTRAINTS a,USER_CONS_COLUMNS b where a.CONSTRAINT_NAME=b.CONSTRAINT_NAME '+

' and a.table_name=b.table_name and constraint_type=''P'' and a.owner=b.owner '+

' and lower(a.owner)=''budget'' order by a.table_name,b.position ';

O1.open;

tableN:='';

O1.First;

ProgressBar1.Max:=O1.RecordCount;

ProgressBar1.Min:=0;

ProgressBar1.Step:=1;

ProgressBar1.Visible :=true;

for i:=0 to O1.RecordCount -1 do

begin

s2.Close;

S2.SQL.Clear;

//判断SQL Server表是否存在当前的字段信息

S2.SQL.Text:='SELECT a.name AS tanme, b.* FROM sysobjects a INNER JOIN '+

' syscolumns b ON a.id = b.id '+

' WHERE (a.xtype = ''U'') AND (a.name = '''+O1.fieldbyname('table_name').AsString+''''+

') and b.name= '''+O1.fieldbyname('COLUMN_NAME').AsString+''''+

' ORDER BY b.id';

S2.Open;

//不存在，输出表明和字段名

if s2.RecordCount<=0 then

begin

Memo1.Text:=Memo1.Text+#13+'表：'''+O1.fieldbyname('table_name').AsString+''''+

' 字段：'''+O1.fieldbyname('COLUMN_NAME').AsString+''' 不存在！';

O1.Next;

tableN:='';

FieldN:='';

Continue;

end;

//是当前表，循环读取主键信息

if (tableN='') or (tableN= O1.fieldbyname('table_name').AsString) then

begin

FieldN:=FieldN+'['+O1.fieldbyname('COLUMN_NAME').AsString+'],';//表明相同或初试时

tableN:= O1.fieldbyname('table_name').AsString;

end

else

begin

with S1 do

begin

try

//取SQL Server表的主键信息

Close;

sql.Clear;

sql.Text:='SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME='''+tableN+'''';

Open;

first;

aa:=fieldbyname('constraint_name').AsString;

//如果该主键在SQL表中已存在，删除该主键信息,重建该表主键

if recordcount>0 then

begin

sql.Clear;

SQL.Text:='ALTER TABLE '+tableN+' DROP CONSTRAINT '+aa; //删除主键

ExecSQL;

end;

SQL.Clear; //COLUMN_NAME

SQL.Text:='ALTER TABLE '+tableN+' WITH NOCHECK ADD '+

' CONSTRAINT [PK_'+tableN+'] PRIMARY KEY NONCLUSTERED '+

' ( '+ copy(FieldN,1,length(FieldN)-1)+

' )';

ExecSQL;

FieldN:='['+O1.fieldbyname('COLUMN_NAME').AsString+'],';

tableN:= O1.fieldbyname('table_name').AsString;

Except

Memo1.Text :=Memo1.Text+'表： '+tableN+' 字段： '+FieldN+' 导入出错！';

exit;

end;

end;

end;

ProgressBar1.StepIt;

Application.ProcessMessages;

O1.Next;

end;

MsgBox('导入完成！');

finally

Screen.Cursor :=crDefault;

ProgressBar1.Visible :=False;

end;

end;