Delphi ADOQuery
Procedure TForm1.Button1Click (Sender: TObject); var A: the Array of String; // definition of dynamic array Index: Integer; // define an array index variable ADOQuery: TADOQuery; the begin ADOQuery: = TADOQuery.create; ADOQuery.SQL.Clear ; ADOQuery.SQL.Add ( ' the Select B from A ' ); ADOQuery.Open; setLength (A, ADOQuery.RecordCount); // set the array width Index: = 0 ; // initialize subscript ADOQuery.First; the While Not ADOQuery the Do .EOF // dataset cycle the begin A [Index]:ADOQuery.FieldByName = ( ' B ' ) .asString; // add data to the array Inc is an (Index); ADOQuery.Next; End ; End ;
Delphi ADOQuery join query the database, insert, delete, modify,
// query record Procedure TForm1.Button1Click (Sender: TObject); the begin ADOQuery.Close; ADOQuery.SQL.Clear; ADOQuery.SQL.Add ( ' SELECT * WHERE query from yourtable ' ); ADOQuery.Open; // insert records Procedure TForm1.Button2Click (Sender: TObject); the begin ADOQuery.Close; ADOQuery.SQL.Clear; ADOQuery.SQL.Text: = " INSERT INTO yourtable (field 1, field 2) values (: 1 ,: field 2 field) ' ; // ADOQuery.SQL.Add ( "INSERT INTO yourtable values (: field 1) '); ADOQuery.Parameters.ParamByName ( ' field 1 ') .Value: = TRIM (Edit1.Text); ADOQuery.Parameters.ParamByName ( ' Field 2 ' ) .Value: = TRIM (Edit2.Text); ADOQuery.ExecSQL; End ; // delete the record Procedure TForm1.Button3Click (Sender : TObject); the begin ADOQuery.Close; ADOQuery.SQL.Clear; ADOQuery.SQL.Text: = " the Delete from fields where yourtable = 3: field 3 ' ; // condition judging where there is not added, when the actual use, attention Analyzing added // ADOQuery.SQL.Add ( 'the Delete from NEW_TABLE WHERE field = 3: field 3'); ADOQuery.Parameters.ParamByName ( ' field 3 ' ) .Value: =TRIM (Edit3.Text); ADOQuery.ExecSQL; // delete the record can also be used DeleteRecords () function Procedure DeleteRecords (AffectRecords: TAffectRecords = ARALL); This function has one parameter: AffectRecords can take the following values: . 1 , arCurrent: delete the current record 2 , arFiltered: delete all records in line (if you use filter filtering if) the filter filter 3 , ARALL: delete all records 4 , arAllChapters: the delete Affects. All Chapters (Chapters ADO) // modify records Procedure TForm1.Button4Click (Sender : TObject); the begin ADOQuery.Close; ADOQuery.SQL.Clear; ADOQuery.SQL.Text: = " the Update yourtable the SET field = 4: field 4 ' ; // not added here where the determination condition, the actual use, note that adding determines // ADOQuery.SQL.Add ( 'field of the Update yourtable the SET = 4: Field 4'); ADOQuery.Parameters.ParamByName ( ' field 4 ' ). the Value: = TRIM (Edit4.Text); ADOQuery.ExecSQL; // immediate updating insert, delete, modify the record is inserted in the above, delete, add the following code to the modified statement: ADOQuery.Close; ADOQuery.SQL. the Add ( ' the SELECT * query from yourtable the WHERE condition ' ); ADOQuery.Open; // Note the use of ADOQuery: 1 , if you need to change the data, query.requestlive must be to true 2 , if there is a time input parameters, error-prone, a general error method is: For example: "the WHERE ABC = : ABC" corrected as follows: "the WHERE ABC =: ABC" That =: Before and after can not be spaces. 3 , ADOQuery.Open and ADOQuery.ExecSQL there are differences. ADOQuery.Open generally used in the query, select the time; and ADOQuery.ExecSQL used in INSERT, the Delete , Update and so on.
Delphi using ADO in connection with a password Access
Delphi using ADO in connection with a password Access var gDBConn: String ; the try self.ADOConnection1.Close; // no password = Connection Password ""; // gDBConn: = 'Provider = the Microsoft.Jet.OLEDB.4.0; Password = ""; the Data Source = MyDB.mdb; of the Persist Security Info = True '; // password OLEDB connection the Jet: Database password = delphi7; gDBConn: = ' Provider = Microsoft.Jet.OLEDB.4.0; the Jet OLEDB: Database password 123456 =; the Source the Data = ' + ExtractFilePath (application.ExeName) + ' MyDB.mdb; the Persist Security Info = True ' ; self.ADOConnection1.ConnectionString: = gDBConn; self.ADOConnection1.Open; the except // The raise; self.ADOConnection1.Close; self.ADOConnection1.Free; application.MessageBox ( ' can not connect to the database! ' , ' Message ' , 64 ); Application.Terminate; End ;
delphi get all the table names, field names database table
var TS: Tstrings; I: Integer; the begin TS: = TStringList. the Create ; // adoconnection1.GetTableNames (TS, to false); // for I: = 0 to ts.Count-do. 1 // ShowMessage ( 'first' + inttostr (i + 1) + 'of the table name is' + ts.Strings); adoconnection1.GetFieldNames ( ' STU ' , TS); for I: = 0 to ts.Count- . 1 do ShowMessage ( ' first ' + IntToStr ( + I . 1 ) + ' field name is ' +ts.Strings); End ; // Note: The above functions can also be done with a session controls