Microsoft KB Archive/194127

= FIX: "Syntax Error" with SQL Literal String Over 16,379 Bytes =

Article ID: 194127

Article Last Modified on 5/17/2007

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APPLIES TO


 * Microsoft Open Database Connectivity Driver for Access 1.0
 * Microsoft Open Database Connectivity Driver for Access 2.0
 * Microsoft Open Database Connectivity Driver for Access 3.0
 * Microsoft Open Database Connectivity Driver for Access 3.5
 * Microsoft Open Database Connectivity Driver for Access 3.6
 * Microsoft Visual Basic 6.0 Professional Edition
 * Microsoft Visual Basic 6.0 Enterprise Edition

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This article was previously published under Q194127



SYMPTOMS
If you attempt to execute a SQL INSERT statement that contains a literal string having over 16,379 characters with the Microsoft ODBC Driver for Access, the following error message occurs:

[Microsoft][ODBC Microsoft Access 97 Driver]

Syntax error in INSERT INTO statement.

SQL UPDATE SQL statements with literal strings over 16,379 bytes also fail with a similar error.



CAUSE
The SQL parser for the Microsoft ODBC Driver for Access prior to 4.0.4202 does not accept string literals larger than 16,379 bytes. This is the defined limit for literal strings in a SQL statement for the Microsoft ODBC Driver for Access.

With the Microsoft ODBC Driver for Access versions 4.0.4202 and later, you can execute a SQL INSERT containing a string literal having over 16,379 characters. However, you will get the following error message with a SQL INSERT that contains a literal string having over 516,076 characters:

[Microsoft][ODBC Microsoft Access Driver]

Query is too complex

This error occurs with both Access 97 and Access 2000 databases.



RESOLUTION
There are two possible workarounds for the syntax error:
 * The Microsoft ODBC Driver for Access versions 4.0.4202 and later allow SQL INSERTS with string literals having up to 516,076 characters.
 * Use parameterized insert or updates rather than embedding literal strings into the SQL statements if you expect to insert or update large string values. This resolution works with all versions of the Microsoft ODBC Driver for Access.



STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

This bug has been fixed in the Microsoft ODBC Driver for Access versions 4.0.4202 and later. Note that version 4.0.4202 of the Odbcjt32.dll file is installed by MDAC 2.1 service pack 2.

However, a new limitation of 516,076 characters now applies.

You may obtain the latest version of the Microsoft Data Access Components from the following Microsoft Web site:

http://msdn2.microsoft.com/en-us/data/aa937695.aspx



Steps to Reproduce Behavior
Run the following sample code to reproduce the problem and demonstrate the workaround. Note that the sample requires a blank Microsoft Access database named c:\db1.mdb and a reference to the Microsoft ActiveX Data Objects Library.

If testing the Microsoft ODBC Driver for Access version 4.0.4202 or later, use the following numbers to test:

In place of 16379, use 516076

In place of 16380, use 516077

Sample Code
' START SAMPLE CODE Sub TestMemo Dim conn As New ADODB.Connection Dim cmd As New ADODB.Command Dim strSQL As String

conn.Open "Driver={Microsoft Access Driver (*.mdb)};" & _ "DBQ=c:\db1.mdb" On Error Resume Next conn.Execute "DROP TABLE tmp_MEMO1234" On Error GoTo 0 conn.Execute "create table tmp_MEMO1234 (data1 memo)"

' Using a parameterized insert works. cmd.ActiveConnection = conn cmd.CommandText = "insert into tmp_MEMO1234 (data1) values (?)" cmd.CommandType = adCmdText cmd.Parameters.Append cmd.CreateParameter("p1", _                           adLongVarChar, adParamInput, -1) cmd.Parameters(0).Value = String(16380, "X") cmd.Execute ' SUCCESS

' Literal string 16379 bytes or less works. strSQL = "insert into tmp_MEMO1234 (data1) values ('" & _              String(16379, "X") & "')" conn.Execute strSQL ' SUCCESS

' Literal string 16380 bytes or larger fails. strSQL = "insert into tmp_MEMO1234 (data1) values ('" & _              String(16380, "X") & "')" conn.Execute strSQL ' FAILS HERE

End Sub ' END SAMPLE CODE

