走向面试之数据库基础:二、SQL进阶之case、子查询、分页、join与视图 一、CASE的两种用法 1.1 等值判断->相当于switch case (1)具体用法模板: CASE expression WHEN value1 THEN returnvalue1...所有可以使用表的地方几乎都可以使用子查询来代替。...如果我们有以下的SQL语句,使用Exists关键字则可以有如下的理解:...
1. dbms_output用法 dbms_output包主要用于调试pl/sql程序,或者在sql*plus命令中显示信息(displaying message)和报表,譬如我们可以写一个简单的匿名pl/sql程序块,而该块出于某种目的使用dbms_output包来显示一些信息。 enable:在serveroutput on的情况下,用来使dbms_output生效(默认即打开) disable:在serverout...
Oracle SQLcl (SQL Developer Command Line) is a Java-based command-line interface for Oracle Database. Using SQLcl, you can execute SQL and PL/SQL statements interactively or as as a batch file. SQLcl provides inline editing, statement completion, command recall, and also supports existing SQL...
Oracle 动态sql 实现方式 1/***2Sample Program 10: Dynamic SQL Method 434This program connects you to ORACLE using your username and5password, then prompts you for a SQL statement. You can enter6any legal SQL statement. Use regular SQL syntax, not embedded SQL.7Your statement will be process...
case语句是一个非常强大的关键字。既可以实现类似于Java中的switch语句的作用。也可以像if语句一样来实现范围的处理。 -- case 语句declarev_agenumber(3):=&输入年龄;begincasewhenv_age<18thendbms_output.put_line('小朋友');whenv_age>18thendbms_output.put_line('成年人');elsedbms_output.put_line(...
sessioncursor其实就是指的跟这个session相对应的server process的PGA里(准确的说是UGA)的一块内存区域(或者说内存结构),它的目的是为了处理且一次只处理一条sql语句。 一个session cursor只能对应一个shared cursor,而一个shared cursor却可能同时对应多个session cursor。
}returnnewstring(list.ToArray()); } } } 表达式树解析 usingFXY.Code.ORM.Mapping;usingSystem;usingSystem.Collections.Generic;usingSystem.Data.Linq.Mapping;usingSystem.Linq;usingSystem.Linq.Expressions;usingSystem.Reflection;usingSystem.Text.RegularExpressions;namespaceFXY.Code.ORM.ExpressionVisit{publicclass...
(); string sql = $"insert into {dataTable.TableName}({string.Join(",", sql_column)}) values ({string.Join(",", sql_para)})"; OracleCommand cmd = new OracleCommand(sql, conn); cmd.Parameters.AddRange(paras.ToArray()); OracleDataAdapter adapter = new OracleDataAdapter(); adapter....
{ return; } switch (status) { case OCI_SUCCESS_WITH_INFO: printf ("OCI_SUCCESS_WITH_INFO:\n"); OCIErrorGet (errhp, (ub4) 1, (text *) 0, &errcode, errbuf, (ub4) sizeof (errbuf), OCI_HTYPE_ERROR); printf ("%s", errbuf); break; case OCI_NEED_DATA: printf ("Error - ...
Using the GDK for E-Mail ProgramsYou can use the GDK LocaleMapper class to retrieve the most commonly used e-mail character set. Call LocaleMapper.getIANACharSetFromLocale, passing in the locale object. The return value is an array of character set names. The first character set returned is ...