在Delphi中使用DBExpress创建数据库？ [英] Creating a Database using DBExpress in Delphi?

问题描述

我需要使用DBExpress以编程方式创建Firebird数据库。我已经在SQL Server上做到了这一点，首先连接到Master，然后将Create脚本传递给查询，但是使用Firebird时，我遇到了一些小问题。

I need to create a Firebird Database programmatically using DBExpress. I have done this for SQL server, by first connecting to Master, then passing in the script for Create to a query, but with Firebird I have a little chicken and egg problem.

推荐答案

我从一个同事那里得到了一个很好的建议，该同事为Freepascal项目创建了一些代码。它没有使用DB Express，但是据他介绍，这是用代码创建数据库的唯一方法。该代码基于InterBase手册，并使用来自gdslib / fbclient dll的调用：

I got a good tip from a collegue that created some code for the Freepascal project. It doesn't use DB express, but according to him it is the only way to create a database with code. This code is based on the InterBase manual, and uses a call from the gdslib / fbclient dll:

procedure TIBConnection.CreateDB;

var ASQLDatabaseHandle,
    ASQLTransactionHandle : pointer;
    CreateSQL : String;
    pagesize : String;
begin
  CheckDisConnected;
  {$IfDef LinkDynamically}
    InitialiseIBase60;
  {$EndIf}
  ASQLDatabaseHandle := nil;
  ASQLTransactionHandle := nil;
  CreateSQL := 'CREATE DATABASE ';
  if HostName <> '' then
    CreateSQL := CreateSQL + ''''+ HostName+':'+DatabaseName + ''''
  else
    CreateSQL := CreateSQL + '''' + DatabaseName + '''';

  if UserName <> '' then
    CreateSQL := CreateSQL + ' USER ''' + Username + '''';
  if Password <> '' then
    CreateSQL := CreateSQL + ' PASSWORD ''' + Password + '''';
  pagesize := params.Values['PAGE_SIZE'];
  if pagesize <> '' then
    CreateSQL := CreateSQL + ' PAGE_SIZE '+pagesize;

  if isc_dsql_execute_immediate(@FStatus[0],@ASQLDatabaseHandle,@ASQLTransactionHandle,length(CreateSQL),@CreateSQL[1],Dialect,nil) <> 0 then
    CheckError('CreateDB', FStatus);

  if isc_detach_database(@FStatus[0], @ASQLDatabaseHandle) <> 0 then
    CheckError('CreateDB', FStatus);

  {$IfDef LinkDynamically}
    ReleaseIBase60;
  {$EndIf}
end;

窍门是isc_dsql_execute_immediate函数。希望这段代码对您有所帮助。以下是此代码来自的Freepascal源文件的链接：

The trick is the isc_dsql_execute_immediate function. I hope this code helps you. Here are the links to the Freepascal source files where this code comes from:

包含CreateDB函数的单元

包含API调用isc_dsql_execute_immediate的单元

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