如何使用sql oracle用批量数据更新CLOB列？

Question

我有 (7A+5dfAA7D...) 字母和数字等数据。其长度大于缺少两个个字符。因此，我无法使用 update 更新该 clob 列，因为它会抛出一个错误，指出字符串文字太长。

如何更新数值？

请帮我。

提前致谢！

Answer 1

下面是一些 Java 代码的一部分，它将文件中的数据插入到 CLOB 列中。技巧是首先插入一个empty_clob()值，然后更新记录。

try {
            /* Register the Oracle driver */
            DriverManager.registerDriver(new OracleDriver());

            /* Establish a connection to the Oracle database. I have used the Oracle Thin driver.
              jdbc:oracle:thin@host:port:sid, "user name", "password" */

            conn = DriverManager.getConnection(connectString, userName, passWord);

            /* Set auto commit to false, it helps to speed up things, by default JDBC's auto commit feature is on.
               This means that each SQL statement is commited as it is executed. */

            conn.setAutoCommit(false);
            stmt = conn.createStatement();

            /* Insert all the data, for the BLOB column we use the function empty_blob(), which creates a locator for the BLOB datatype.
               A locator is an object that ponts to the actual location of the BLOB data in the database. A locator is essential to manipulate BLOB data. */

            query = "INSERT INTO CLOB_TABLE (id,data_clob,bestandsnaam,dt_geplaatst) " +
                    "VALUES(" + ID + ", empty_clob(),\'" + fileName + "\',sysdate)";

            //System.out.println(query);

            stmt.execute(query);

            /* Once the locator has been inserted, we retrieve the locator by executing a SELECT statement 
               with the FOR UPDATE clause to manually lock the row. */

            query = "SELECT DATA_CLOB FROM CLOB_TABLE WHERE ID=\'" + ID + "\' FOR UPDATE";

            //System.out.println(query);
            rs = stmt.executeQuery(query);
            //System.out.println("Select statement uitgevoerd");

            if (rs.next()) {

                /* Once a locator has been retrieved we can use it to insert the binary data into the database. */
                CLOB clob = (CLOB)((OracleResultSet)rs).getClob(1);
                os = clob.getAsciiOutputStream();
                final File f = new File(fileName);
                is = new FileInputStream(f);
                final byte[] buffer = new byte[clob.getBufferSize()];
                int bytesRead = 0;
                while ((bytesRead = is.read(buffer)) != -1) {
                    os.write(buffer, 0, bytesRead);
                }
                clob = null;
                returnValue = 0;
            }


        } catch

Answer 2

您可以使用 SQL*Loader 加载数据，但必须从文件中执行。尽管您可能会编写一个脚本来设置包含数据的顺序文件，但这可能会或可能不会困难，具体取决于涉及的数据量。

对于名为 TEST 的表，其中包含 TEST_ID 和 TEST_BLOB 列：

Control.dat:

load data
infile data.dat
replace 
into table TEST
Fields terminated by ','
(
  TEST_ID, 
   lob_file FILLER CHAR,
  TEST_CLOB LOBFILE(lob_file) TERMINATED BY EOF
)

data.dat:

1,c:\work\clob1_data.dat
2,c:\work\clob2_data.dat
etc...

C:\Work>sqlldr USER/[email protected] control=control.txt
sqlldr USER/[email protected] control=control.txt
SQL*Loader: Release 10.2.0.1.0 - Production on Thu Sep 24 01:20:06 2009
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Commit point reached - logical record count 2

此配置源自以下示例： 问汤姆