I'm connecting to old FoxPro 2.6 tables in Delphi 2007.
I've installed the BDE and I put a TTable on the form.
One table doesn't work
Set the databasename to c:\datadir and
The tablename to contacts.dbf.
When I set active to true, I get
invalid index descriptor.
Another table works fine
I have another table called article.dbf that loads fine, and in the original program everything works fine as well.
Here's what I've tried
I've already re-indexed everything in the original program, but that makes no difference.
In fact the diagnostic from Foxpro says that everything is OK.
I don't really care about any indexes because there are not that many records in the table.
I've tried setting the indexfile property, but that doesn't help.
How do I get Delphi to just connect to the table and stop complaining about indexes?
Probably your contacts.dbf table contains expression index that cannot be evaluated by BDE. Here is an explanation I have found here
Question: What types of FoxPro indexes
are not supported by the BDE? When
trying to open some tables, I get an
"Invalid Index Descriptor" error.
Answer: This error occurs when the
production index (.CDX) associated the
table has an index tag which has an
expression which the BDE cannot
evaluate. The solution is to delete
the tag using FoxPro create an
eqivalent index that the BDE can
understand.
The following conditions are not
supported by the BDE and will cause
"Invalid Index Descriptor" error.
DTOC(, 1) format not supported; Use
DTOC(). ALLTRIM function not
supported; Use LTRIM(RTRIM(Field)).
Here's code that Sertac described that will remove the auto-open CDX flag from the header. Make a copy of the dataabase first, of course.
var
Stream: TFileStream;
ByteRead: Byte;
begin
Stream := TFileStream.Create("YourFile.dbf", fmOpenReadWrite or fmShareDenyNone);
try
// Byte offset 28 has a value of 0x01 if a structural (auto-open) index exists,
// or 0x00 if no such index exists. If the value is not set, we do nothing.
Stream.Position := 28;
Stream.Read(ByteRead, SizeOf(ByteRead));
if ByteRead = 1 then
begin
ByteRead := 0;
Stream.Position := 28;
Stream.Write(ByteRead, SizeOf(Byte));
end;
finally
Stream.Free;
end;
end;
Related
Using either Delphi 10.2 or 10.3, FireDAC and either Firebird 2.5 or 3.0: I've used the JVCL TJvAppStorage components for years and never had a problem with them, either to INI/XML storage or to a table in an AbsoluteDB database. I'm trying to migrate an app from AbsoluteDB to Firebird via FireDAC, and can't get the TJvAppDBStorage to write entries - it returns no errors, but nothing actually gets written into the table.
I have a datamodule containing the FireDAC connection and driver components, the JvAppDBStorage, a TDataSource and a TFDTable component. The FDB exists containing an appropriate table, the TFDTable is open on that table, the JvAppDBStorage has its properties set to match the table's fields, and the TFDTable, datasource and JvAppDBStorage are properly linked. (This all mirrors what has existed and worked against AbsoluteDB.) A call to dmStorage.FBStorage.WriteString(dmStorage.FBStorage.ConcatPaths(['General', 'LastStarted']), FormatDateTime(StdDTFmtStr, Now)); does not throw any exceptions, but nothing actually gets written into the table. Doing a normal append/set fields/post construct via the TFDTable works properly.
Any help appreciated!
Steve
There are 3 critical parts to this:
The underlying table must have a PK. I have an ID column with an associated sequence with before-insert trigger to make an auto-inc column for my PK, and an index that's a merge of the SectionID and KeyID fields to speed up the Locate() calls.
When creating the TFDTable object, you must create a new TFDTransaction object and attach it to the TFDTable and the TFDConnection.
On the TFDTable, you must set UpdateOptions.UpdateMode to upWhereKeyOnly. If you only do the first two steps, reads and appends will work but edits will not.
function TFDDBMgr.MakeTableObj(const ATblName: String): TFDTable;
begin
Result := TFDTable.Create(Self);
with Result do begin
//hook up all our needed stuff
Connection := Self.Connection;
TableName := ATblName;
CachedUpdates := False;
{...}
//!!.SS 09/11/19: REQUIRED for TJvAppDBStorage use,
//also requires that a PK be defined on the table
UpdateOptions.UpdateMode := upWhereKeyOnly;
Transaction := TFDTransaction.Create(Result);
Transaction.Connection := Self.Connection;
end;
end;
I wanted to create a new mdb file containing tables based on the structure of previously existing tables. I knew that I can use newTable.FieldDefs.Add() to recreate the fields one by one in a loop. But since there is already an oldTable fully stocked with the correct FieldDefs, that seemed terribly inelegant. I was looking for a single-statement solution!
I had found that newTable.FieldDefs.Assign(oldTable.FieldDefs) would compile (and run) without error but it left newTable with zero defined fields. This caused me to erroneously conclude that I didn't understand that statement's function. (Later I found that it failed only when oldTable.open had not occurred, which could not happen when the database was not available, even though the FieldDefs had been made Persistent and were clearly visible in the Object Inspector)
Here is my original code after some sleuthing:
procedure TForm2.Button1Click(Sender: TObject);
var
fname: string;
Table: TFDTable;
FDConn: TFDConnection;
begin
fname := 'C:\ProgramData\mymdb.mdb';
if FileExists(fname) then DeleteFile(fname);
{ Make new file for Table }
FDMSAccessService1.Database := fname;
FDMSAccessService1.DBVersion := avAccess2000;
FDMSAccessService1.CreateDB;
{ Connect to new file }
FDConn := TFDConnection.Create(nil);
FDConn.Params.Database := fname;
FDConn.Params.DriverID := 'MSAcc';
FDConn.Connected := true;
{ Set up new Table using old table's structure }
Table := TFDTable.Create(nil);
try
{ ADOTable1 has been linked to an existing table in a prior
database with Field Defs made Persistent using the Fields
Editor in the Object Inspector. That database will not be
available in my actual use scenario }
try
ADOTable1.open; // Throws exception when database file not found
except
end;
Table.Connection := FDConn;
{ specify table name }
Table.TableName := ADOTable1.TableName;
Table.FieldDefs.Assign(ADOTable1.FieldDefs); // No errors reported
ShowMessageFmt('New Table %s has %d fields',[Table.TableName,
Table.FieldDefs.Count]);
{ Reports correct TableName but "0 fields" with table not open
(i.e. file not found). Reports "23 fields" with table open }
{ Set Table definition into new mdb file }
Table.CreateTable(False); // Throws exception when 0 fields found
finally
Table.Free;
end;
end;
It turned out that the solution was to use a ClientDataSet originally linked to the same old database instead of the ADOTable. See the working solution below in my answer.
Edit: A final note. I had hoped to use this FireDAC approach, as indicated here, to get around the lack of a TADOTable.CreateTable method. Alas, although the "solutions" above and below do work to create a new TADOTable, that table's field definitions are not faithful replicas of the original table. There may be a combination of the myriad TFDTable options that would get around this, but I was not able to discover it so I reverted to creating my ADO tables with SQL.
Thanks to #Ken White's (unfortunately deleted) pointer, I now think that I have a solution to my original question about cloning the field defs from an old table into a newly created database. My original problem stemmed from the fact that the FieldDefs function for a table evidently does not return the actual stored field data if the table is not "open" (i.e., connected to the relevant database). Since my use scenario would not have a valid database available I could not "open" the table. However, ClientDataSets have an additional option to "StoreDefs" along with editor options to "Fetch Params" and "Assign Local Data". With those settings saved, the ClientDataSet renders its FieldDefs properties without being "open". Using that approach it seems that I can clone the stored field defs to a new table without needing a currently valid database to read them from. Thanks again, Ken, you saved a lot of my remaining hair! I sure wish that Embarcadero would do a better job of rationalizing their help files. They removed BDE from the default installation of Rio while still pointing in their help file discussion on creating Access tables to its TTable type as the way to create new tables and then never point to the equivalent capabilities in FireDAC (or elsewhere) which they continue to support. I wasted a lot of time because of this "oversight"!
Here is my working code after Ken's tip:
procedure TForm1.Button1Click(Sender: TObject);
var
i: integer;
fname: string;
Table: TFDTable;
FDConn: TFDConnection;
begin
fname := 'C:\ProgramData\mymdb.mdb';
if FileExists(fname) then DeleteFile(fname);
FDMSAccessService1.Database := fname;
FDMSAccessService1.DBVersion := avAccess2000;
FDMSAccessService1.CreateDB;
FDConn := TFDConnection.Create(nil);
FDConn.Params.Database := fname;
FDConn.Params.DriverID := 'MSAcc';
FDConn.Connected := true;
Table := TFDTable.Create(nil);
try
Table.Connection := FDConn;
{ specify table name }
Table.TableName := 'ATable';
{ The existingClientDataSet has been linked to a table in the
prior, no longer valid, database using StoreDefs, Fetch Params,
and Assign Local Data in the Object Inspector }
Table.FieldDefs.Assign(existingClientDataSet.FieldDefs);
ShowMessageFmt('New Table has %d fields', [Table.FieldDefs.Count]);
Table.CreateTable(False);
finally
Table.Free;
end;
Hello fellow StackOverflowers,
Currently I'm facing a situation where it seems that there is a maximum length for the Database property of a TSQLConnection object in Delphi.
When I open the connection to my database I get the following error when I use a rather long (154 chars) database name:
dbExpress Error: [0x0015]: Connection failed
SQL Server Error: unrecognized database parameter block
wrong version of database parameter block
When I relocate my database file to another location (and with that reduce the length of the path) it will connect to the database.
I am currently using the Object Inspector to set the connection properties of the TSQLConnection object.
Basically, my question comes down to this:
Does a TSQLConnection have a maximum length for the values set in the Params property? And if so, what is the maximum length of these values?
Update
I've found two ways to open a copy of Employee.Gdb in a folder with a 160-character name ('abcdefghij0123456789' x 8).
What I did firstly was to edit the DBXConnections.Ini file and changed the Database parameter in the [IBConnection] section to read
Database=localhost:D:\abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890\employee.gdb
Then, I can successfully connect to it, open the Employee.Gdb and make changes to the Customer table. I have verified the changes in IBConsole just in case the copy of Employee.Gdb wasn't the one I assumed it was.
Subsequently, I've found that I can create and open the db in code using Delphi Seattle and Interbase XE7, as follows:
function LongPath : String;
begin
Result := 'D:\' + DupeString('abcdefghij0123456789', 8);
end;
function LongDBName : String;
begin
Result := LongPath + '\Employee.Gdb';
end;
procedure TForm1.OpenDB;
var
Ini : TMemIniFile;
const
scDBXConIni = 'C:\Users\Public\Documents\Embarcadero\Studio\dbExpress\17.0\dbxconnections.ini';
scSourceDB = 'D:\Delphi\Databases\Interbase\Employee.Gdb';
begin
Ini := TMemIniFile.Create(scDBXConIni);
try
// First, blank out the Database value in the IBConnection section
// of DBXConnections.Ini
Ini.WriteString('IBConnection', 'Database', '');
Ini.UpdateFile;
// Next, create the long-named directory and copy Employee.Gdb to it
if not DirectoryExists(LongPath) then
MkDir(LongPath);
Assert(CopyFile(PChar(scSourceDB), PChar(LongDBName), False));
// Set LoadParamsOnConnect to False so that the SqlConnection uses
// the value of the Database we are about to give it
SqlConnection1.LoadParamsOnConnect := False;
SqlConnection1.Params.Values['Database'] := LongDBName;
SqlConnection1.Connected := True;
// Open the CDS to view the data
CDS1.Open;
finally
Ini.Free;
end;
end;
The critical step in doing it this way is setting LoadParamsOnConnect to False, which I confess I'd overlooked in earlier attempts to get this code to work.
I've got some earlier versions of Delphi on this machine, so if you're not using Seattle and the above code doesn't work for you, tell me which one you are using and I'll see if I can try that.
**[Original answer]
Actually, I think that this may be an error occurring in one of the DBX DLLs.
I created a folder with a 160-character name, then copied the demo Employee.Gdb database into it. Interbase XE7's IBConsole can open the db without error. So could a small test project contructed with IBX components in Delphi Seattle.
However, with an equivalent DBX project, when I use the code below
procedure TForm1.Button1Click(Sender: TObject);
begin
SqlConnection1.Params.Values['database'] := 'D:\abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890abcdefghij01234567890\employee.gdb';
SqlConnection1.Connected := True;
end;
I get an error in
procedure TDBXDynalinkConnection.DerivedOpen;
var
Count: TInt32;
Names: TWideStringArray;
Values: TWideStringArray;
IsolationLevel: Longint;
DBXError: TDBXErrorCode;
begin
Count := FConnectionProperties.Properties.Count;
FConnectionProperties.GetLists(Names, Values);
CheckResult(FMethodTable.FDBXConnection_Connect(FConnectionHandle, Count, Names, Values));
DBXError := FMethodTable.FDBXConnection_GetIsolation(FConnectionHandle, IsolationLevel);
'I/O error for file "database.gdb"
Error while trying to open file
The operation completed successfully'
and the Database param of the SqlConnection is left at the value 'Database.Gdb', which is not the value I specified, of course, nor was it the value specified in the params in the IDE, which was 'd:\delphi\databases\interbase\employee.gdb'.
I wondered if I could work around this problem by SUBSTing a drive to the 'abcdefg ...' path. I tried that and opening the database as "x:\employee.gdb" , but I get the same error in my DBX app, and also IBConsole cannot access the db either.
I think you need a shorter physical path!**
This is related to MSSql Server:
As a general guideline, long path names greater than 160 characters
might cause problems.
from Microsoft TechNet - https://technet.microsoft.com/en-us/library/ms165768(v=sql.105).aspx
I am using Delphi 7 with the FibPlus components . One of them being TpFIBQuery.
I am loading data from a table with the generic
select * from TableName where Key = 1
One of the fields returned is of type BLOB(Text).
I can't seem to get the value into a string list informatie using either of the following 3 ways :
Informatie.Text := FieldByName('Informatie').AsString // Returns the string 'BLOB'
Informatie.Text := BlobAsString('Informatie') // Returns ''
BlobToStrings('Informatie',Informatie) // Returns ''
I have confirmed using Database Workbench that the field in the table indeed contains the saved text.
Anyone ?
usualy, i do like this
var
sl: TStrings; // blob IS NOT string!
ms: TMemoryStream;
begin
sl := TStringList.Create;
ms := TMemoryStream.Create;
try
q.FieldByName('x').SaveToStream(ms);
ms.Position := 0;
sl.LoadFromStream(ms);
// do what ever you want with sl here
// and here too
finally
sl.Free;
ms.Free;
end; // try..finally
end;
note that q is your TpFibQuery object.
also
select * from table is bad bad practice.
that habit eventually will lead you continuous headache.
After trying the solution of #jiang, which produced the same error, I finally have found the culprit.
Turns out it was an error due to my part ( it usually is, you just have to find it ).
Turns out I had set the read transaction to False sometime during the processing/reading of the fields of the original query.
I perform a lookup in another table to get the description of a integer value in the query.
This lookup query uses the same read transaction , and sets this transaction to False after looking up the description.
AFter returning to the original query, reading integer and string fields pose no problem (although the read transaction has been set to False), but reading a BLOB field into a string with the ...AsString method produces an error or returns 'BLOB'.
Obviously I need to set the read transaction to True at the start of the read actions and set it to False after ALL read transactions. This is the major change when you convert a Paradox BDE application to a Firebird of Sqlserver application.
Anyway, I am glad I have found the solution. Hopefully it will help others too.
I have a firebird 2.x database with Generator and a trigger to generate the key field.
I need to get the returned value from below query.
INSERT INTO XXXX (vdate,description) values ('"+ VDate +"','"+ Description +"') returning vno INTO :ParamVoucherNo
I tried several versions of below code but it dont wrok and I get
Dynamic sql error sql error code = -104
Is it really possible to get the return value in delphi using TIBQuery ?
Query1->SQL->Clear();
Query1->SQL->Add("INSERT INTO XXXX (vodate,description) values ('"+ VDate +"','"+ Description +"') returning vno INTO :ParamVoucherNo");
Query1->Params->ParamByName("ParamVoucherno")->ParamType = ptResult;
Query1->Params->ParamByName("ParamVoucherno")->DataType = ftInteger;
Query1->Params->ParamByName("ParamVoucherno")->Value = "";
Query1->Prepare();
Query1->ExecSQL();
Any suggestions?
From Firebird README.returning:
The INTO part (i.e. the variable list) is allowed in PSQL only (to
assign local variables) and rejected in DSQL.
As IBX uses DSQL, you should exclude INTO part from your query.
INSERT ... RETURNING for DSQL looks the same as a call of a stored procedure, which returns result set. So, you have to use Open instead of ExecSQL.
Your mixing of dynamic SQL with parameters is just confusing.
Do this instead:
Query1->SQL->Clear();
Query1->SQL->Add("INSERT INTO table1 (vodate,description) VALUES"+
"(:VoDate,:Description) RETURNING vno INTO :VoucherNo ");
Query1->Params->ParamByName("VoDate")->Value = VDate;
Query1->Params->ParamByName("description")->Value = Description;
Query1->Prepare();
Query1->ExecSQL();
VoucherNo = Query1->Params->ParamByName("VoucherNo")->AsInteger;
Using Delphi 6 I have the ID returning successfully using an EXECUTE BLOCK statement:
EXECUTE BLOCK
RETURNS ( DeptKey INT )
AS
BEGIN
INSERT INTO DEPARTMENT
( COMPANY_KEY, DEPARTMENT_NAME )
VALUES ( 1, 'TEST1' ) RETURNING DEPARTMENT_KEY INTO :DeptKey;
SUSPEND;
END;
From Delphi you can do the folliowing:
FQuery.SQL.Text := '<Execute Block Statement>';
FQuery.Open();
ANewKey := FQuery.Fields[0].AsInteger;
IBX is not Firebird ready
you can take a look at FIBPLUS who support Firebird features
FIBPlus also supports FB2.0 insert ... into ... returning. Now you
should not bother about getting generator values from the client but
leave them in the trigger. You can also use RDB$DB_KEY. New possible
variants of work with insert returning and RDB$DB_KEY are shown in the
example “FB2InsertReturning”.
Why not get the next value for VoucherNo first, followed by
"INSERT INTO table1 (vno, vodate,description) VALUES (:VoucherNo,:VoDate,:Description)");
?
Your trigger can then either be dispensed with (which is nice), or modified to detect null (or <= zero can be useful too) and only then populate the vno field.
create trigger bi_mytable
active before insert position 1
on mytable
as
begin
if (new.vno is null)
then new.vno = next value for gen_VoucherNos;
end
Client-side you can :
select gen_id(gen_VoucherNos, 1) from rdb$database;
By modifying the trigger in this manner you save yourself a headache later on if/when you want to insert blocks of records
I wonder if that INSERT can be wrapped into EXECUTE BLOCK command.
Would IBX manage EXECUTE BLOCK then?
http://www.firebirdsql.org/refdocs/langrefupd20-execblock.html
http://firebirdsql.su/doku.php?id=execute_block
Hope to try it in both IBX and Unified Interbase in XE2
PS: Even if it does not, I found the library, that tells to work on top of IBX of Delphi XE2 (both x86 and x64) and to add EXECUTE BLOCK support: http://www.loginovprojects.ru/index.php?page=ibxfbutils#eb.
As I know there should be some changes to IBX made. Internally INSERT ... RETURNING should be treated the same way as a selectable procedure with returning parameters.
i know this question was answered a long time ago, but i must write this as clear as possible, for those who need this as i was.
i too, needed the "INSERT..RETURNING" thing.
the Delphi drove me crazy for a long time, until i changed my Data access components.
i even moved from Delphi XE2, to XE5 only because of that...
conclusion : IBX does NOT support RETURNING!
FireDAC is PERFECT for what i need with Firebird.
just move to FireDAC and you'll be able to do everything you need, and with high performance.
If you have a table with this 2 Fields: GRP_NO and GROUPNAME and you want to get the new GRP_NO you have to use RET_ as prefix, see example:
procedure TFormDatenbank.Button1Click(Sender: TObject);
var
q: Uni.TUniQuery;
ID: Integer;
GroupName: String;
begin
GroupName := 'MyGroupName';
q := TUniQuery.Create(nil);
try
q.Connection := Datenmodul.UniConnection;
q.ParamCheck := true; // the default value of ParamCheck is true.
q.SQL.Clear;
q.SQL.Add('SELECT GRP_NO, GROUPNAME FROM GROUPDATA WHERE GROUPNAME = :GROUPNAME');
q.ParamByName('GROUPNAME').AsString := GroupName;
q.Open;
if q.RecordCount > 0 then
ID := q.FieldByName('GRP_NO').AsInteger
else
begin
// there exist no group with this name, so insert this new name
q.SQL.Clear;
q.SQL.Add('INSERT INTO GROUPDATA');
q.SQL.Add('(GROUPNAME)');
q.SQL.Add('VALUES');
q.SQL.Add('(:GROUPNAME)');
q.SQL.Add('RETURNING GRP_NO;');
q.ParamByName('GROUPNAME').AsString := GroupName;
q.Execute;
ID := q.ParamByName('RET_GRP_NO').AsInteger;
end;
finally
q.Free;
end;
end;
From the IBx2 sources, you can do it like this:
//Uses IBSql;
//var Cur: IResults;
IBSQL1.SQL.Text := 'delete from tbl_document where id = 120 returning id;';
IBSQL1.Prepare;
if IBSQL1.Prepared then
begin
Cur := IBSQL1.Statement.Execute(IBTransaction1.TransactionIntf);
WriteLn(Cur.Data[cou].AsString);
Cur.GetTransaction.Commit(True);
end;
IResults interface Code:
IResults = interface
function getCount: integer;
function GetTransaction: ITransaction;
function ByName(Idx: String): ISQLData;
function getSQLData(index: integer): ISQLData;
procedure GetData(index: integer; var IsNull:boolean; var len: short; var data: PChar);
procedure SetRetainInterfaces(aValue: boolean);
property Data[index: integer]: ISQLData read getSQLData; default;
property Count: integer read getCount;
end;
Test enviroment:
Arch Linux X86
Firebird 3
Lazarus 1.9
FPC 3.0.4
Quick note: This works on new Firebird API in the IBX, But I didn't test it in Legacy Firebird API with the IBX.