Handling exception examples We’ll use the film table from the sample database for the demonstration. 1) Handling no_data_found exception example The following example issues an error because the film id 2000 does not exist. do $$ declare rec record; v_film_id int = 2000; begin -- selec...
The rest of the code in xact.c are routines to support the creation and finishing of transactions and subtransactions. For example, AtStart_Memory takes care of initializing the memory subsystem at main transaction start. Subtransaction Handling Subtransactions are implemented using a stack of Trans...
For example, it could be an IntegerField or a CharField. Most field types are permitted, with the exception of those handling relational data (ForeignKey, OneToOneField and ManyToManyField) and file fields ( FileField and ImageField). 可以嵌套数组字段——你可以指定一个 ArrayField 的实例作为 base_...
这里还处在存储过程的申明阶段 IS --创建了一个函数,判断全局变量是否大于参数CREDIT_LIMIT,如果大于则局部赋值为CREDIT_LIMIT,且返回是否大于情况 rating NUMBER := 1; over_limit BOOLEAN; BEGIN IF check_credit.rating <= credit_limit THEN -- reference global variable引用全局变量 over_limit := FALSE; E...
In PostgreSQL, ICU locales can be used by creating one in the database using theCREATE COLLATIONcommand. An example is: CREATE COLLATION english (provider = icu, locale = 'en-US'); The basic structure of ICU collation names is simliar to that of libc collations: a language code, followed...
Example scenario Consider a situation where a SQL exception occurs. Without global exception handling, the client might receive an obscure error message that exposes the internal details of your application. Error without global exception handling: ...
Error handling When an error occurs when executing a SQL statement SQLAPI++ library throws an exception of type SAException and SAException::ErrPos method returns error position in the SQL statement. In PostgreSQL server SAException::ErrPos method returns -1 because PostgreSQL does not support thi...
There is another function called “NULLIF”[3], returns NULL if first and second arguments are equal, otherwise returns the first argument, here is the example where we are comparing 10 with 10 and we already know that these are equal so it will return NULL. In the second example, we ar...
Note that we have usedIS DISTINCT FROMrather than the common!=here as the latter has problems handling NULL values. By returning 'NEW' we are forcing any UPDATE which includes a new value forpasswordto also update thepassword_changedfield to today's date. ...
To ensure tasks can run normally, DRS provides automatic pre-check. Before starting a DRS task, DRS checks the configurations and conditions of the source and destination databases. For details about the main check items and handling suggestions, seePre-check Items. In addition to the pre-check...