为什么我会收到“未实现跨数据库引用”？

Question

对 postgresql 数据库的非常简单的更新，但它不起作用。 sql select 语句很好，并返回正确的值。

当我进行更新时，它会抛出错误：

 {"ERROR [0A000] ERROR: cross-database references are not implemented: "openerp.public.product_template"; Error while executing the query"}.

我正在使用 vb.net 和 postgresql 9.2。

我想要做的只是更改名称字段以匹配描述中的内容。

log:
LOG 0   duration: 34.000 ms  statement: SELECT * FROM product_template where import_date = '08/22/2013'
LOG 0   duration: 11.000 ms  statement: select n.nspname, c.relname, a.attname, a.atttypid, t.typname, a.attnum, a.attlen, a.atttypmod, a.attnotnull, c.relhasrules, c.relkind, c.oid, d.adsrc from (((pg_catalog.pg_class c inner join pg_catalog.pg_namespace n on n.oid = c.relnamespace and c.oid = 20496) inner join pg_catalog.pg_attribute a on (not a.attisdropped) and a.attnum > 0 and a.attrelid = c.oid) inner join pg_catalog.pg_type t on t.oid = a.atttypid) left outer join pg_attrdef d on a.atthasdef and d.adrelid = a.attrelid and d.adnum = a.attnum order by n.nspname, c.relname, attnum
LOG 0   duration: 12.000 ms  parse _PLAN000000001D2CFB60: SELECT * FROM product_template where import_date = '08/22/2013'
LOG 0   duration: 11.000 ms  statement: select ta.attname, ia.attnum, ic.relname, n.nspname, tc.relname from pg_catalog.pg_attribute ta, pg_catalog.pg_attribute ia, pg_catalog.pg_class tc, pg_catalog.pg_index i, pg_catalog.pg_namespace n, pg_catalog.pg_class ic where tc.oid = 20496 AND tc.oid = i.indrelid AND n.oid = tc.relnamespace AND i.indisprimary = 't' AND ia.attrelid = i.indexrelid AND ta.attrelid = i.indrelid AND ta.attnum = i.indkey[ia.attnum-1] AND (NOT ta.attisdropped) AND (NOT ia.attisdropped) AND ic.oid = i.indexrelid order by ia.attnum
LOG 0   duration: 0.000 ms  statement: select current_schema()
LOG 0   duration: 1.000 ms  statement: select c.relhasrules, c.relkind, c.relhasoids from pg_catalog.pg_namespace u, pg_catalog.pg_class c where u.oid = c.relnamespace and c.relname = 'product_template' and u.nspname = 'public'
LOG 0   duration: 1.000 ms  statement: select c.relhasrules, c.relkind, c.relhasoids from pg_catalog.pg_namespace u, pg_catalog.pg_class c where u.oid = c.relnamespace and c.relname = 'product_template' and u.nspname = 'public'
ERROR   0A000   cross-database references are not implemented: "openerp.public.product_template"

代码：

Private Sub btnChgNameToDescr_Click(sender As Object, e As EventArgs) Handles btnChgNameToDescr.Click

    Dim objConn As New System.Data.Odbc.OdbcConnection
    Dim objCmd As New System.Data.Odbc.OdbcCommand
    Dim dtAdapter As New System.Data.Odbc.OdbcDataAdapter
    Dim ds As New DataSet

    Me.Cursor = System.Windows.Forms.Cursors.WaitCursor

    Dim strConnString As String
    Dim strSQL As String
    Dim iRecCount As Integer

    Me.Cursor = System.Windows.Forms.Cursors.WaitCursor

    If objConn.State = ConnectionState.Open Then
        'do nothing
    Else
        strConnString = "Dsn=PostgreSQL35W;database=OpenERP;server=localhost;port=5432;uid=openpg;pwd=openpgpwd"
        objConn.ConnectionString = strConnString
        objConn.Open()
    End If


    If Me.txtImportDate.Text = "" Then
        MsgBox("Import Date field cannot be blank.")
        Exit Sub
    End If

    Dim str_import_date As String = Me.txtImportDate.Text


    strSQL = "SELECT * FROM product_template where import_date = " & "'" & str_import_date & "'"

    dtAdapter.SelectCommand = objCmd

    With objCmd
        .Connection = objConn
        .CommandText = strSQL
        .CommandType = CommandType.Text
        .ExecuteNonQuery()

        dtAdapter.Fill(ds, "product_template")

        iRecCount = ds.Tables("product_template").Rows.Count

    End With

    If iRecCount = 0 Then
        MsgBox("No records found.")
        Me.Cursor = System.Windows.Forms.Cursors.Default
        Exit Sub
    End If


    Dim cb As New Odbc.OdbcCommandBuilder(dtAdapter)


    'change the name field to item_description
    With ds
        For i As Integer = 0 To .Tables("product_template").Rows.Count - 1

            'this works, returns a string
            Dim str_default_code As String = (.Tables(0).Rows(i).Item("name").ToString)
            'this works
            Dim str_item_description As String = (.Tables(0).Rows(i).Item("description").ToString)

            .Tables("product_template").Rows(i).Item("name") = str_item_description
            'setting the variable doesn't work either - Dim str_item_description As String = "BH LITE BRT"

            'this throws the error
            dtAdapter.Update(ds, "product_template")

        Next
    End With

    Me.Cursor = System.Windows.Forms.Cursors.Default
End Sub

Answer 1

如果您在 DBeaver 中遇到此错误，将目标数据库设置为活动可能会解决它：

这与multi-database support有关

Answer 2

在您的 postgresql 日志中查找错误以查看实际发送到数据库的内容。我不知道如何修复您的代码，因为我不太了解该平台。此外，您需要转向参数化查询，因为您当前的方法将受到 sql 注入问题的影响。

但是，您的错误意味着您有一个额外的命名空间。正常的命名空间是schema.table.column 或schema.table，具体取决于上下文。如果您尝试将表指定为schema.table.column，它将读取为database.schema.table 并抛出此错误。同样，如果您有一个额外的点，您可能会意外指定 database.schema.table.column（这也会引发错误）。

这就是为什么字符串化 SQL 确实是个坏主意的部分原因，但并没有真正触及问题的表面。

Answer 3

我在使用 DataGrip（2020.3 版）时遇到了同样的问题。

发生这种情况是因为我更改了连接设置，但仍然使用相同的控制台窗口。

我找到了两种解决方法：

1. 更改控制台的会话（在控制台右键-->切换会话-->新建会话）
2. 打开一个新的控制台窗口

Answer 4

今天正在做某事并得到了这个 - 最后是因为我的数据库名称中有大写字母，而命令没有 - prodCRT.public.tablename vs. prodcrt.public.tablename

只要我将架构重命名为小写，我之前工作的所有命令都会再次工作。

注意：原来的数据库只被称为“prod”——所以当我把它叫做 prodCRT 时事情就坏了

Answer 5

在对带有前缀架构名称的表进行截断时，发现 Redshift 出现同样的错误。

截断 schema_name.table_name;

虽然从 S3 加载复制是在没有架构名称的情况下完成的。 总而言之，Truncate table 应该与 Copy 命令中使用的模式相同，以避免在 Redshift 中出现此错误。

https://docs.aws.amazon.com/redshift/latest/dg/r_TRUNCATE.html