SQL Server Compact ‘Data Directory’ macro in Connection String – more info needed

connection-stringdatadirectorynetsql serversql-server-ce

So, as described on this msdn page, when you define a Connection String for
SQL Server Compact 3.5, you can use the "Data Directory" macro, like this:

quote from this msdn page:

Data Directory Support
SQL Server Compact 3.5 now supports the Data Directory macro. This means that if you add the string |DataDirectory| (enclosed in pipe symbols) to a file path, it will resolve to the path of the database.

For example, consider the connection string:

"Data Source= c:\program files\MyApp\Mydb.sdf"

When using Data Directory, you can instead use the following connection string:

"Data Source = |DataDirectory|\Mydb.sdf"

For more information, see How to: Deploy a SQL Server Compact 3.5 Database with an Application.

However, the 'for more information' link on msdn doesn't actually give any more information.

So my question is:

How does the |Data Directory| macro translate at run time? For WinForm apps, it seems to just give the location of the executable. Or is it more complicated than that?

Best Answer

To set the DataDirectory property, call the AppDomain.SetData method. If you do not set the DataDirectory property, the following default rules will be applied to access the database folder:

For applications that are put in a folder on the user's computer, the database folder uses the application folder.
For applications that are running under ClickOnce, the database folder uses the specific data folder that is created.

Related Solutions

Sql – How to concatenate text from multiple rows into a single text string in SQL Server

If you are on SQL Server 2017 or Azure, see Mathieu Renda answer.

I had a similar issue when I was trying to join two tables with one-to-many relationships. In SQL 2005 I found that XML PATH method can handle the concatenation of the rows very easily.

If there is a table called STUDENTS

SubjectID       StudentName
----------      -------------
1               Mary
1               John
1               Sam
2               Alaina
2               Edward

Result I expected was:

SubjectID       StudentName
----------      -------------
1               Mary, John, Sam
2               Alaina, Edward

I used the following T-SQL:

SELECT Main.SubjectID,
       LEFT(Main.Students,Len(Main.Students)-1) As "Students"
FROM
    (
        SELECT DISTINCT ST2.SubjectID, 
            (
                SELECT ST1.StudentName + ',' AS [text()]
                FROM dbo.Students ST1
                WHERE ST1.SubjectID = ST2.SubjectID
                ORDER BY ST1.SubjectID
                FOR XML PATH ('')
            ) [Students]
        FROM dbo.Students ST2
    ) [Main]

You can do the same thing in a more compact way if you can concat the commas at the beginning and use substring to skip the first one so you don't need to do a sub-query:

SELECT DISTINCT ST2.SubjectID, 
    SUBSTRING(
        (
            SELECT ','+ST1.StudentName  AS [text()]
            FROM dbo.Students ST1
            WHERE ST1.SubjectID = ST2.SubjectID
            ORDER BY ST1.SubjectID
            FOR XML PATH ('')
        ), 2, 1000) [Students]
FROM dbo.Students ST2

C# Equivalent of SQL Server DataTypes

This is for SQL Server 2005. There are updated versions of the table for SQL Server 2008, SQL Server 2008 R2, SQL Server 2012 and SQL Server 2014.

SQL Server Data Types and Their .NET Framework Equivalents

The following table lists Microsoft SQL Server data types, their equivalents in the common language runtime (CLR) for SQL Server in the System.Data.SqlTypes namespace, and their native CLR equivalents in the Microsoft .NET Framework.

SQL Server data type          CLR data type (SQL Server)    CLR data type (.NET Framework)  
varbinary                     SqlBytes, SqlBinary           Byte[]  
binary                        SqlBytes, SqlBinary           Byte[]  
varbinary(1), binary(1)       SqlBytes, SqlBinary           byte, Byte[] 
image                         None                          None

varchar                       None                          None
char                          None                          None
nvarchar(1), nchar(1)         SqlChars, SqlString           Char, String, Char[]     
nvarchar                      SqlChars, SqlString           String, Char[] 
nchar                         SqlChars, SqlString           String, Char[] 
text                          None                          None
ntext                         None                          None

uniqueidentifier              SqlGuid                       Guid 
rowversion                    None                          Byte[]  
bit                           SqlBoolean                    Boolean 
tinyint                       SqlByte                       Byte 
smallint                      SqlInt16                      Int16  
int                           SqlInt32                      Int32  
bigint                        SqlInt64                      Int64 

smallmoney                    SqlMoney                      Decimal  
money                         SqlMoney                      Decimal  
numeric                       SqlDecimal                    Decimal  
decimal                       SqlDecimal                    Decimal  
real                          SqlSingle                     Single  
float                         SqlDouble                     Double  

smalldatetime                 SqlDateTime                   DateTime  
datetime                      SqlDateTime                   DateTime 

sql_variant                   None                          Object  
User-defined type(UDT)        None                          user-defined type     
table                         None                          None 
cursor                        None                          None
timestamp                     None                          None 
xml                           SqlXml                        None

Best Answer

Related Solutions

Sql – How to concatenate text from multiple rows into a single text string in SQL Server

C# Equivalent of SQL Server DataTypes

SQL Server Data Types and Their .NET Framework Equivalents

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