函数TO_CHAR、TO_NCHAR、TO_CLOB、TO_NCLOB、TO_NUMBER、TO_BINARY_DOUBLE 和 TO_BINARY_FLOAT 具有布尔重载,用于将布尔值转换为数字或字符类型。 函数TO_BOOLEAN 语法: 使用TO_BOOLEAN 将字符值表达式或数值表达式显式转换为布尔值。 如果expr 是字符串,则它的计算结果必须为允许的字符串输入。 expr 可以采用...
--插入一行通过使用 EMPTY_CLOB( ) to 建立一个lob locator INSERT INTO waterfalls (falls_name,falls_directions) VALUES ('Munising Falls',EMPTY_CLOB( )); --获得lob locator,上面插入的数据,因为我们插入的是一个empty_clob(),那么lob locator不指向任何数据,虽然给变量分配了只 SELECT falls_directions I...
9.导出格式介绍:Dmp格式:.dmp是二进制文件,可跨平台,还能包含权限,效率好; Sql格式:.sql格式的文件,可用文本编辑器查看,通用性比较好,效率不如第一种,适合小数据量导入导出。尤其注意的是表中不能有大字段 (blob,clob,long),如果有,会报错; Pde格式:.pde格式的文件,.pde为PL/...
SELECT id, DBMS_LOB.GETLENGTH(image) AS image_length FROM example_table WHERE id = 1; 查询CLOB数据 SELECT id, DBMS_LOB.SUBSTR(content, 100) AS content_substr FROM example_table WHERE id = 2; 查询NCLOB数据 SELECT id, DBMS_LOB.TO_LOB(long_text) AS long_text_lob FROM example_table WHE...
For example, the // .Net StreamReader makes it easier to convert the raw bytes // into actual characters. StreamReader streamreader = new StreamReader(clob, Encoding.Unicode); char[] cbuffer = new char[100]; while((actual = streamreader.Read(cbuffer, 0, cbuffer.Length)) >0) Console...
example 1.动态PL/SQL,对CLOB字段操作可传递表名table_name,表的唯一标志字段名field_id,clob字段名field_name记录号v_id,开始处理字符的位置v_pos,传入的字符串变量v_clob 修改CLOB的PL/SQL过程:updateclob create or replace procedure updateclob(table_name in varchar2,field_id in varchar2...
Example // C# using System; using Oracle.DataAccess.Client; using Oracle.DataAccess.Types; class OracleClobSample { static void Main() { string constr = "User Id=scott;Password=tiger;Data Source=oracle"; OracleConnection con = new OracleConnection(constr); con.Open(); OracleClob clob = new...
This technique is used primarily to test whether aLOBreturned from the server is NULL, as this example illustrates: C# if(myLob == OracleLob.Null) A NULLLOBbehaves similarly to a zero-byteLOBin thatReadsucceeds and always returns zero bytes. ...
适合小数据量导入导出。尤其注意的是表中不能有大字段 (blob,clob,long),如果有,会报错; Pde格式:.pde格式的文件,.pde为PL/SQL Developer自有的文件格式,只能用PL/SQL Developer工具 导入导出,不能用文本编辑器查看; 10.确定操作者的账号权限。
// To write, you can use any of the stream classes, or write raw binary data using // the OracleLob write method. Writing character vs. binary is the same; // however note that character is always in terms of Unicode byte counts // (for example: even number of bytes - 2 byte...