设置数据库(SQLite)for Unity [英] Setup Database (SQLite) for Unity
问题描述
我看了太多的教程，无法列出，它们都推荐相同的东西.但是，他们并没有帮助解决我的问题.
我试图在我的项目中包含一个SQLite数据库，并且在为PC，MAC和在Linux Standalone(在Windows机器上进行测试)下，数据库可以正常运行.在Android设备上进行测试时，出现以下错误.
E/Unity: ArgumentException: Invalid ConnectionString format for parameter "/storage/emulated/0/Android/data/com.tbltools.tbl_project/files/TBLDatabase.db"
at Mono.Data.Sqlite.SqliteConnection.ParseConnectionString (System.String connectionString) [0x00000] in <filename unknown>:0
at Mono.Data.Sqlite.SqliteConnection.Open () [0x00000] in <filename unknown>:0
at UIHandler+<RequestAllStudentNames>c__Iterator2.MoveNext () [0x00000] in <filename unknown>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) [0x00000] in <filename unknown>:0
我认为对connectionString进行修改应该很简单，但这并没有解决我的问题.这是我到目前为止的内容:
if (Application.platform != RuntimePlatform.Android)
{
// The name of the db.
tblDatabase = "URI=file:" + Application.dataPath + "/TBLDatabase.db"; //returns the complete path to database file exist.
}
else
{
tblDatabase = Application.persistentDataPath + "/TBLDatabase.db";
if (!File.Exists(tblDatabase))
{
// if it doesn't ->
Debug.LogWarning("File \"" + tblDatabase + "\" does not exist. Attempting to create from \"" + Application.dataPath + "!/assets/" + "TBLDatabase.db");
// open StreamingAssets directory and load the db ->
// #if UNITY_ANDROID
var loadDb = new WWW("jar:file://" + Application.dataPath + "!/assets/" + "TBLDatabase.db"); // this is the path to your StreamingAssets in android
while (!loadDb.isDone) { } // CAREFUL here, for safety reasons you shouldn't let this while loop unattended, place a timer and error check
// then save to Application.persistentDataPath
File.WriteAllBytes(tblDatabase, loadDb.bytes);
}
}
//open db connection
var connection = new SqliteConnection(tblDatabase);
connection.Open();
var command = connection.CreateCommand();
我已经使用adb shell并将数据库从我的Android设备中拉出，并且一切都按预期进行(该数据库确实存在并且它不为空).
我相信我拥有所有相关的dll文件，但是如果有人可以给我一些指导，我将不胜感激.
*************************************************** ****编辑********************************************* *
此后，我根据给出的建议进行了以下更改.
我现在正在调用以下方法来启动我的连接并处理数据库请求StartCoroutine(RunDbCode(dbFileName, jsonStudentID, jsonIndiNames, jsonIndiStudentNumbers));
然后我有以下方法:
IEnumerator RunDbCode(string fileName, List jsonStudentID, List jsonIndiNames, List jsonIndiStudentNumbers)
{
//Where to copy the db to
string dbDestination = Path.Combine(Application.persistentDataPath, "data");
dbDestination = Path.Combine(dbDestination, fileName);
//Check if the File do not exist then copy it
if (!File.Exists(dbDestination))
{
//Where the db file is at
string dbStreamingAsset = Path.Combine(Application.streamingAssetsPath, fileName);
byte[] result;
//Read the File from streamingAssets. Use WWW for Android
if (dbStreamingAsset.Contains("://") || dbStreamingAsset.Contains(":///"))
{
WWW www = new WWW(dbStreamingAsset);
yield return www;
result = www.bytes;
}
else
{
result = File.ReadAllBytes(dbStreamingAsset);
}
Debug.Log("Loaded db file");
//Create Directory if it does not exist
if (!Directory.Exists(Path.GetDirectoryName(dbDestination)))
{
Directory.CreateDirectory(Path.GetDirectoryName(dbDestination));
}
//Copy the data to the persistentDataPath where the database API can freely access the file
File.WriteAllBytes(dbDestination, result);
Debug.Log("Copied db file");
}
//Now you can do the database operation
//open db connection
var connection = new SqliteConnection(dbDestination);
connection.Open();
var command = connection.CreateCommand();
// Drop the table if it already exists.
command.CommandText = "DROP TABLE IF EXISTS existing_individual;";
command.ExecuteNonQuery();
var sql = "CREATE TABLE existing_individual (studentID VARCHAR(23), fullName VARCHAR(50), studentNumber VARCHAR(20))";
command.CommandText = sql;
command.ExecuteNonQuery();
//Inserting the exisiting student names returned, into the SQLite DB
int count = 0;
foreach (var individuals in jsonStudentID)
{
//looping through the existing students registered for the individual quiz - below has been written to avoid SQL injection
sql = "INSERT INTO existing_individual (studentID, fullName, studentNumber) VALUES (@jsonStudentID, @jsonIndiNames, @jsonIndiStudentNumbers)";
command.Parameters.AddWithValue("@jsonStudentID", jsonStudentID[count]);
command.Parameters.AddWithValue("@jsonIndiNames", jsonIndiNames[count]);
command.Parameters.AddWithValue("@jsonIndiStudentNumbers", jsonIndiStudentNumbers[count]);
command.CommandText = sql;
command.ExecuteNonQuery();
count++;
}
//close the connection
command.Dispose();
command = null;
connection.Close();
connection = null;
}
但是，我仍然遇到以下错误:
06-08 15:26:56.498 16300-16315/? E/Unity: ArgumentException: Invalid ConnectionString format for parameter "/storage/emulated/0/Android/data/com.tbltools.tbl_project/files/data/TBLDatabase.db"
at Mono.Data.Sqlite.SqliteConnection.ParseConnectionString (System.String connectionString) [0x00000] in <filename unknown>:0
at Mono.Data.Sqlite.SqliteConnection.Open () [0x00000] in <filename unknown>:0
at UIHandler+<RunDbCode>c__Iterator3.MoveNext () [0x00000] in <filename unknown>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) [0x00000] in <filename unknown>:0
UnityEngine.MonoBehaviour:StartCoroutineManaged2(IEnumerator)
UnityEngine.MonoBehaviour:StartCoroutine(IEnumerator)
<RequestAllStudentNames>c__Iterator2:MoveNext()
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)
(Filename: Line: -1)
06-08 15:26:56.502 16300-16315/? E/Unity: ArgumentException: Invalid ConnectionString format for parameter "URI"
at Mono.Data.Sqlite.SqliteConnection.ParseConnectionString (System.String connectionString) [0x00000] in <filename unknown>:0
at Mono.Data.Sqlite.SqliteConnection.Open () [0x00000] in <filename unknown>:0
at UIHandler.CreateIndiButton () [0x00000] in <filename unknown>:0
at UIHandler+<RequestAllStudentNames>c__Iterator2.MoveNext () [0x00000] in <filename unknown>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) [0x00000] in <filename unknown>:0
我还将数据库添加到"StreamingAssets"文件夹中，如下图所示:
下面还显示了包含我的dll文件的我的plugins文件夹的图像.
有关该主题的大多数教程已过时.
看了一下代码，发现很少的问题，但是我不能确定这些是否是导致此错误的原因.应该在协程函数中使用WWW，以便您可以通过在while循环内添加yield return null来让出或等待loadDb.isDone完成.您也可以自己生成WWW请求，这就是我将在答案中使用的方法.
此外，jar:file://" + Application.dataPath是旧代码.为此使用Application.streamingAssetsPath.此外，您不需要"URI=file:" + Application.dataPath.只需使用Application.persistentDataPath即可.
我将只介绍如何进行设置.
设置管理的"代码部分:
1 .转到您的Unity安装路径
<UnityInstallationDirecory>\Editor\Data\Mono\lib\mono\2.0
复制以下文件:
-
I18N.MidEast.dll -
I18N.Other.dll -
I18N.Rare.dll -
I18N.West.dll -
Mono.Data.Sqlite.dll -
Mono.Data.SqliteClient.dll -
System.Data.dll
到项目的<ProjectName>\Assets\Plugins路径.
这将允许您从Mono.Data.Sqlite命名空间编译API，而不会出现任何错误.
设置未管理的代码部分:
在此步骤中，您将需要获取本机Sqlite库.您可以获取源代码，对其进行构建和使用，或使用已经预编译的binray./p>
1 .获取用于 Windows
的本机库从sqlite3.dll >此处，并将其放在<ProjectName>\Assets\Plugins\x86_64路径中.
如果使用Windows 32位，则从sqlite3.dll版本>此处，并将其放在<ProjectName>\Assets\Plugins\x86路径中.
2 .获取 Android
的本机库从 Android ARM处理器下载预编译的libsqlite3.so
此处并将其放入<ProjectName>\Assets\Plugins\Android\libs\armeabi-v7a路径.
从以下位置下载用于 Android Intel x86处理器的预编译的libsqlite3.so
此处，并将其放在<ProjectName>\Assets\Plugins\Android\libs\x86路径.
这涵盖了Android设备上使用的大多数处理器.
3 .获取 UWP
的本机库 A .下载WSA文件夹，然后将WSA文件夹放在<ProjectName>\Assets\Plugins路径中.该文件夹包含本机部分.
B .在<ProjectName>\Assets路径中创建两个名为"mcs.rsp" 和"csc.rsp" 的文件.
C .在"mcs.rsp" 和"csc.rsp" 文件中添加以下内容:
-r:I18N.MidEast.dll
-r:I18N.Other.dll
-r:I18N.Rare.dll
-r:I18N.West.dll
-r:Mono.Data.Sqlite.dll
-r:Mono.Data.SqliteClient.dll
-r:System.Data.dll
D .为UWP进行构建时，必须将托管的dll移动到项目的 root 文件夹中.因此，将I18N.MidEast.dll，I18N.Other.dll，I18N.Rare.dll，I18N.West.dll，Mono.Data.Sqlite.dll，Mono.Data.SqliteClient.dll，System.Data.dll移至<ProjectName>路径非 <ProjectName>\Assets\Plugins路径.
4 .对于iOS，Linux和Mac，您无需为其下载其他任何文件或执行此步骤.它们通常具有内置的本地预编译Sqlite库.
将数据库文件包含在内部版本中:
1 .在<ProjectName>\Assets文件夹中创建一个文件夹，并将其命名为 StreamingAssets .拼写很重要，并且区分大小写.
2 .将数据库文件(TBLDatabase.db)放在此 StreamingAssets 文件夹中.
在构建项目后访问数据库文件
Sqlite无法处理构建中 StreamingAssets 文件夹中的文件，因为这是只读路径.另外，Android要求您使用WWW API而不是标准的System.IO API来读取 StreamingAssets 文件夹.您必须将db文件从Application.streamingAssetsPath/filename.db复制到Application.persistentDataPath/filename.db.
在某些平台上，要求您在Application.persistentDataPath内创建一个文件夹，然后将数据保存到该文件夹.总是这样做.下面的示例代码中的文件夹为数据"，因此将变为Application.persistentDataPath/data/filename.db.
3 .由于上述原因，请检查数据库文件是否存在于
Application.persistentDataPath/data/filename.db.如果是这样，请使用Application.persistentDataPath/data/filename.db作为数据库操作的路径.如果不是，请从#4继续.
4 .读取数据库文件并将其从 StreamingAssets 文件夹复制到Application.persistentDataPath
在某些平台上，要求您在Application.persistentDataPath内创建一个文件夹，然后将数据保存到该文件夹.总是这样做.下例中的文件夹是数据".
如果这是Android，请检测并使用WWW从Application.streamingAssetsPath/filename.db读取到文件.使用File.ReadAllBytes可以在Android以外的任何其他设备上读取它.在您的示例中，您为此使用了Application.platform.在我的示例中，我将简单地检查路径中是否包含"://"或:///来做到这一点.
5 .读取文件后，用File.WriteAllBytes将刚读取的数据写入Application.persistentDataPath/data/filename.db.现在，您可以使用此路径进行数据库操作.
6 .将"URI=file:"前缀为Application.persistentDataPath/data/filename.db路径，这是在Sqlite API的数据库操作中应使用的路径.
了解所有这些信息非常重要，以便在发生某些更改时对其进行修复，但是我已经完成了下面的#3 至#6 的步骤.
IEnumerator RunDbCode(string fileName)
{
//Where to copy the db to
string dbDestination = Path.Combine(Application.persistentDataPath, "data");
dbDestination = Path.Combine(dbDestination, fileName);
//Check if the File do not exist then copy it
if (!File.Exists(dbDestination))
{
//Where the db file is at
string dbStreamingAsset = Path.Combine(Application.streamingAssetsPath, fileName);
byte[] result;
//Read the File from streamingAssets. Use WWW for Android
if (dbStreamingAsset.Contains("://") || dbStreamingAsset.Contains(":///"))
{
WWW www = new WWW(dbStreamingAsset);
yield return www;
result = www.bytes;
}
else
{
result = File.ReadAllBytes(dbStreamingAsset);
}
Debug.Log("Loaded db file");
//Create Directory if it does not exist
if (!Directory.Exists(Path.GetDirectoryName(dbDestination)))
{
Directory.CreateDirectory(Path.GetDirectoryName(dbDestination));
}
//Copy the data to the persistentDataPath where the database API can freely access the file
File.WriteAllBytes(dbDestination, result);
Debug.Log("Copied db file");
}
try
{
//Tell the db final location for debugging
Debug.Log("DB Path: " + dbDestination.Replace("/", "\\"));
//Add "URI=file:" to the front of the url beore using it with the Sqlite API
dbDestination = "URI=file:" + dbDestination;
//Now you can do the database operation below
//open db connection
var connection = new SqliteConnection(dbDestination);
connection.Open();
var command = connection.CreateCommand();
Debug.Log("Success!");
}
catch (Exception e)
{
Debug.Log("Failed: " + e.Message);
}
}
用法:
string dbFileName = "TBLDatabase.db";
void Start()
{
StartCoroutine(RunDbCode(dbFileName));
}
I have looked at too many tutorials to list and they all recommend the same thing. However, they have not helped to solve my problem.
I am trying to include in my project an SQLite DB, and when building for PC, MAC & Linux Standalone (testing on a Windows machine), the database works as expected. When testing on an Android device, I get the following errors.
E/Unity: ArgumentException: Invalid ConnectionString format for parameter "/storage/emulated/0/Android/data/com.tbltools.tbl_project/files/TBLDatabase.db"
at Mono.Data.Sqlite.SqliteConnection.ParseConnectionString (System.String connectionString) [0x00000] in <filename unknown>:0
at Mono.Data.Sqlite.SqliteConnection.Open () [0x00000] in <filename unknown>:0
at UIHandler+<RequestAllStudentNames>c__Iterator2.MoveNext () [0x00000] in <filename unknown>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) [0x00000] in <filename unknown>:0
I thought that making an amendment to the connectionString should be simple enough, but that hasn't solved my problem. This is what I have so far:
if (Application.platform != RuntimePlatform.Android)
{
// The name of the db.
tblDatabase = "URI=file:" + Application.dataPath + "/TBLDatabase.db"; //returns the complete path to database file exist.
}
else
{
tblDatabase = Application.persistentDataPath + "/TBLDatabase.db";
if (!File.Exists(tblDatabase))
{
// if it doesn't ->
Debug.LogWarning("File \"" + tblDatabase + "\" does not exist. Attempting to create from \"" + Application.dataPath + "!/assets/" + "TBLDatabase.db");
// open StreamingAssets directory and load the db ->
// #if UNITY_ANDROID
var loadDb = new WWW("jar:file://" + Application.dataPath + "!/assets/" + "TBLDatabase.db"); // this is the path to your StreamingAssets in android
while (!loadDb.isDone) { } // CAREFUL here, for safety reasons you shouldn't let this while loop unattended, place a timer and error check
// then save to Application.persistentDataPath
File.WriteAllBytes(tblDatabase, loadDb.bytes);
}
}
//open db connection
var connection = new SqliteConnection(tblDatabase);
connection.Open();
var command = connection.CreateCommand();
I have used adb shell and pulled the DB from my Android device and everything is as expected (the DB does exist and it isn't empty).
I believe I have all the relevant dll files, but if anyone could give me some guidance I would appreciate it.
***************************************************EDIT**********************************************
I have since made the following alterations based on advice given.
I am now calling the following method to start my connection and handle DB requestsStartCoroutine(RunDbCode(dbFileName, jsonStudentID, jsonIndiNames, jsonIndiStudentNumbers));
Then I have the following method:
IEnumerator RunDbCode(string fileName, List jsonStudentID, List jsonIndiNames, List jsonIndiStudentNumbers)
{
//Where to copy the db to
string dbDestination = Path.Combine(Application.persistentDataPath, "data");
dbDestination = Path.Combine(dbDestination, fileName);
//Check if the File do not exist then copy it
if (!File.Exists(dbDestination))
{
//Where the db file is at
string dbStreamingAsset = Path.Combine(Application.streamingAssetsPath, fileName);
byte[] result;
//Read the File from streamingAssets. Use WWW for Android
if (dbStreamingAsset.Contains("://") || dbStreamingAsset.Contains(":///"))
{
WWW www = new WWW(dbStreamingAsset);
yield return www;
result = www.bytes;
}
else
{
result = File.ReadAllBytes(dbStreamingAsset);
}
Debug.Log("Loaded db file");
//Create Directory if it does not exist
if (!Directory.Exists(Path.GetDirectoryName(dbDestination)))
{
Directory.CreateDirectory(Path.GetDirectoryName(dbDestination));
}
//Copy the data to the persistentDataPath where the database API can freely access the file
File.WriteAllBytes(dbDestination, result);
Debug.Log("Copied db file");
}
//Now you can do the database operation
//open db connection
var connection = new SqliteConnection(dbDestination);
connection.Open();
var command = connection.CreateCommand();
// Drop the table if it already exists.
command.CommandText = "DROP TABLE IF EXISTS existing_individual;";
command.ExecuteNonQuery();
var sql = "CREATE TABLE existing_individual (studentID VARCHAR(23), fullName VARCHAR(50), studentNumber VARCHAR(20))";
command.CommandText = sql;
command.ExecuteNonQuery();
//Inserting the exisiting student names returned, into the SQLite DB
int count = 0;
foreach (var individuals in jsonStudentID)
{
//looping through the existing students registered for the individual quiz - below has been written to avoid SQL injection
sql = "INSERT INTO existing_individual (studentID, fullName, studentNumber) VALUES (@jsonStudentID, @jsonIndiNames, @jsonIndiStudentNumbers)";
command.Parameters.AddWithValue("@jsonStudentID", jsonStudentID[count]);
command.Parameters.AddWithValue("@jsonIndiNames", jsonIndiNames[count]);
command.Parameters.AddWithValue("@jsonIndiStudentNumbers", jsonIndiStudentNumbers[count]);
command.CommandText = sql;
command.ExecuteNonQuery();
count++;
}
//close the connection
command.Dispose();
command = null;
connection.Close();
connection = null;
}
However, I am still getting the following errors:
06-08 15:26:56.498 16300-16315/? E/Unity: ArgumentException: Invalid ConnectionString format for parameter "/storage/emulated/0/Android/data/com.tbltools.tbl_project/files/data/TBLDatabase.db"
at Mono.Data.Sqlite.SqliteConnection.ParseConnectionString (System.String connectionString) [0x00000] in <filename unknown>:0
at Mono.Data.Sqlite.SqliteConnection.Open () [0x00000] in <filename unknown>:0
at UIHandler+<RunDbCode>c__Iterator3.MoveNext () [0x00000] in <filename unknown>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) [0x00000] in <filename unknown>:0
UnityEngine.MonoBehaviour:StartCoroutineManaged2(IEnumerator)
UnityEngine.MonoBehaviour:StartCoroutine(IEnumerator)
<RequestAllStudentNames>c__Iterator2:MoveNext()
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)
(Filename: Line: -1)
06-08 15:26:56.502 16300-16315/? E/Unity: ArgumentException: Invalid ConnectionString format for parameter "URI"
at Mono.Data.Sqlite.SqliteConnection.ParseConnectionString (System.String connectionString) [0x00000] in <filename unknown>:0
at Mono.Data.Sqlite.SqliteConnection.Open () [0x00000] in <filename unknown>:0
at UIHandler.CreateIndiButton () [0x00000] in <filename unknown>:0
at UIHandler+<RequestAllStudentNames>c__Iterator2.MoveNext () [0x00000] in <filename unknown>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) [0x00000] in <filename unknown>:0
I have also added my database to the 'StreamingAssets' folder as shown in the image below:
Below also shows an image of my plugins folder that holds my dll files.
Most tutorials on this topic are outdated.
Looked at the code and found few problems but I can't tell if those are the reason you are getting this error. WWW should be used in a coroutine function so that you can yield or wait for loadDb.isDone is finish by adding yield return null inside the while loop. You can also yield the WWW request itself and that's the method I will use in my answer.
Also, jar:file://" + Application.dataPath is an old code. Use Application.streamingAssetsPath for that. Furthermore, you don't need "URI=file:" + Application.dataPath. Just use Application.persistentDataPath for that.
I will just put an instruction on how to do the setup.
Setting up the MANAGED code part:
1.Go to your Unity installation path
<UnityInstallationDirecory>\Editor\Data\Mono\lib\mono\2.0
Copy the following files:
I18N.MidEast.dllI18N.Other.dllI18N.Rare.dllI18N.West.dllMono.Data.Sqlite.dllMono.Data.SqliteClient.dllSystem.Data.dll
to the project's <ProjectName>\Assets\Plugins path.
This will allow you to compile API from the Mono.Data.Sqlite namespace without any error.
Setting up the UNMANAGED code part:
In this step, you will need to get the native Sqlite library. You can get the source code, build it and use it or use already pre-compiled binray.
1.Get the native library for Windows
Download the pre-compiled sqlite3.dll for Windows 64 bit from here, and put it in the <ProjectName>\Assets\Plugins\x86_64 path.
If using Windows 32 bit then get the sqlite3.dll version from here and put it in the <ProjectName>\Assets\Plugins\x86 path.
2.Get the native library for Android
Download the pre-compiled libsqlite3.so for Android ARM processor from
here and put it in the <ProjectName>\Assets\Plugins\Android\libs\armeabi-v7a path.
Download the pre-compiled libsqlite3.so for Android Intel x86 processor from
here and put it in the <ProjectName>\Assets\Plugins\Android\libs\x86 path.
This covers most processors used on Android devices.
3.Get the native library for UWP
A.Download the WSA folder then put the WSA folder in the <ProjectName>\Assets\Plugins path. That folder contains the native part.
B.Create 2 files named "mcs.rsp" and "csc.rsp" in the <ProjectName>\Assets path.
C.Add the following inside the "mcs.rsp" and "csc.rsp" files:
-r:I18N.MidEast.dll
-r:I18N.Other.dll
-r:I18N.Rare.dll
-r:I18N.West.dll
-r:Mono.Data.Sqlite.dll
-r:Mono.Data.SqliteClient.dll
-r:System.Data.dll
D.You will have to move the managed dlls to the root folder of the project when building for UWP. So, move I18N.MidEast.dll, I18N.Other.dll, I18N.Rare.dll, I18N.West.dll, Mono.Data.Sqlite.dll, Mono.Data.SqliteClient.dll, System.Data.dll to the <ProjectName> path not <ProjectName>\Assets\Plugins path.
4.For iOS, Linux and Mac, it looks like you don't have to download anything else for them or do this step. They usually have the native pre-compiled Sqlite libraries built-in.
Including the Database file in the Build:
1.Create a folder in your <ProjectName>\Assets folder and name it StreamingAssets. Spelling counts and it's case sensitive.
2.Put the database file (TBLDatabase.db) in this StreamingAssets folder.
Accessing the Database File after building the project
Sqlite cannot work on files in the StreamingAssets folder in a build since that's a read-only path. Also, Android requires that you use the WWW API instead of the standard System.IO API to read from the StreamingAssets folder. You have to copy the db file from Application.streamingAssetsPath/filename.db to Application.persistentDataPath/filename.db.
On some platforms, it is required that you create a folder inside Application.persistentDataPath and save data to that folder instead. Always do that. The folder in the example code below is "data" so that will become Application.persistentDataPath/data/filename.db.
3.Because of the statement above, check if the database file exist in the
Application.persistentDataPath/data/filename.db. If it does, use Application.persistentDataPath/data/filename.db as a path for your database operation. If it doesn't, continue from #4.
4.Read and copy the database file from the StreamingAssets folder to Application.persistentDataPath
On some platforms, it is required that you create a folder inside Application.persistentDataPath and save data to that folder instead. Always do that. The folder in the example below is "data".
Detect if this is Android and use WWW read to the file from Application.streamingAssetsPath/filename.db. Use File.ReadAllBytes to read it on anything else other than Android. In your example, you used Application.platform for that. In my example, I will simply check if the path contains "://" or :/// to do that.
5.Once you read the file, write the data you just read to Application.persistentDataPath/data/filename.db with File.WriteAllBytes. Now, you can use this path for your database operation.
6.Prefix "URI=file:" to the Application.persistentDataPath/data/filename.db path and that's the path for that should be used in your database operation with the Sqlite API.
It's very important that you understand all these in order to fix it when something changes but I've already done step #3 to #6 below.
IEnumerator RunDbCode(string fileName)
{
//Where to copy the db to
string dbDestination = Path.Combine(Application.persistentDataPath, "data");
dbDestination = Path.Combine(dbDestination, fileName);
//Check if the File do not exist then copy it
if (!File.Exists(dbDestination))
{
//Where the db file is at
string dbStreamingAsset = Path.Combine(Application.streamingAssetsPath, fileName);
byte[] result;
//Read the File from streamingAssets. Use WWW for Android
if (dbStreamingAsset.Contains("://") || dbStreamingAsset.Contains(":///"))
{
WWW www = new WWW(dbStreamingAsset);
yield return www;
result = www.bytes;
}
else
{
result = File.ReadAllBytes(dbStreamingAsset);
}
Debug.Log("Loaded db file");
//Create Directory if it does not exist
if (!Directory.Exists(Path.GetDirectoryName(dbDestination)))
{
Directory.CreateDirectory(Path.GetDirectoryName(dbDestination));
}
//Copy the data to the persistentDataPath where the database API can freely access the file
File.WriteAllBytes(dbDestination, result);
Debug.Log("Copied db file");
}
try
{
//Tell the db final location for debugging
Debug.Log("DB Path: " + dbDestination.Replace("/", "\\"));
//Add "URI=file:" to the front of the url beore using it with the Sqlite API
dbDestination = "URI=file:" + dbDestination;
//Now you can do the database operation below
//open db connection
var connection = new SqliteConnection(dbDestination);
connection.Open();
var command = connection.CreateCommand();
Debug.Log("Success!");
}
catch (Exception e)
{
Debug.Log("Failed: " + e.Message);
}
}
Usage:
string dbFileName = "TBLDatabase.db";
void Start()
{
StartCoroutine(RunDbCode(dbFileName));
}
这篇关于设置数据库(SQLite)for Unity的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
