Difference between revisions of "SQLiteDatabase.OpenBLOB"
From Xojo Documentation
m (Gperlman moved page SQLiteDatabase.OpenBlob to SQLiteDatabase.OpenBLOB) |
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| Line 1: | Line 1: | ||
<ShowIf version=2013r1> | <ShowIf version=2013r1> | ||
{{MethodBox | {{MethodBox | ||
| − | | name= | + | | name=OpenBLOB |
| owner=[[SQLiteDatabase]] | | owner=[[SQLiteDatabase]] | ||
| ownertype=class | | ownertype=class | ||
| scope=public | | scope=public | ||
| parameters=tableName As String, columnName As String, row As UInt64, readWrite As Boolean, databaseName As String = "" | | parameters=tableName As String, columnName As String, row As UInt64, readWrite As Boolean, databaseName As String = "" | ||
| − | | returntype=[[ | + | | returntype=[[SQLiteBLOB]] |
| platform=all | | platform=all | ||
}} | }} | ||
| Line 30: | Line 30: | ||
data = data + blob.Read(1000) | data = data + blob.Read(1000) | ||
If blob.ReadError Then | If blob.ReadError Then | ||
| − | + | MessageBox("Error reading from BLOB.") | |
Exit While | Exit While | ||
End If | End If | ||
| Line 40: | Line 40: | ||
== See Also == | == See Also == | ||
| − | [[ | + | [[SQLiteBLOB]], [[SQLiteDatabase.CreateBLOB]] |
</ShowIf> | </ShowIf> | ||
Latest revision as of 19:30, 18 February 2022
Method
SQLiteDatabase.OpenBLOB(tableName As String, columnName As String, row As UInt64, readWrite As Boolean, databaseName As String = "") As SQLiteBLOB
Supported for all project types and targets.
Supported for all project types and targets.
Opens a BLOB column for the specified table and column at the specified row (rowID).
Notes
- The row parameter is the rowid value, and not the actual row number, for example if you only have one record in your database, with a rowid of 100 then you would pass in a row of 100 and not 1 for example.
- Pass in false as the readWrite parameter to open the blob for reading only.
- The blob cannot be resized
- Creating a new blob automatically zeros the entire blob
- The row must exist when calling CreateBlob, it does not create a new record for you
Example
This example reads the Logo (stored as a binary picture) from the Logo column for rowID = 1 in the Team table:
Var blob As SQLiteBlob
blob = db.OpenBlob("Team", "Logo", 1, True)
If blob <> Nil Then
Var data As String
While Not blob.EOF
data = data + blob.Read(1000)
If blob.ReadError Then
MessageBox("Error reading from BLOB.")
Exit While
End If
Wend
blob.Close
// Do something with the data
End If
blob = db.OpenBlob("Team", "Logo", 1, True)
If blob <> Nil Then
Var data As String
While Not blob.EOF
data = data + blob.Read(1000)
If blob.ReadError Then
MessageBox("Error reading from BLOB.")
Exit While
End If
Wend
blob.Close
// Do something with the data
End If