Sql interview question explain ref cursor strongly typed ref cursor and weakly typed ref c oracle pl sql interview question explain ref cursor strongly typed ref cursor and weakly typed ref c click here to subscribe. This works better when you have multiple lines to type and erase. On the other hand, a weaklytyped cursor can work with a result set of any shape. Plsql reference type can be of explicitimplicit type and cursor variable. To return a weakly typed cursor variable as an output parameter, the cursor must be. When you opt to use a weakly typed cursor, you can anchor it to a plsql structure that is a collection of a plsql record structure. A weakly typed ref cursor has a return type that is dependant on the sql statement it executes, i. Cursor variables inherit the properties of the cursor data types upon which they are based. A weakly typed cursor variable one without a return type previously declared within the current scope. Strongly typed ref cursor the ref cursor type is restricted to an individual return type using the return clause.
Packages are used in plsql for partitioning functionality. The plsql block can continue to use the cursor variable after this line is executed. What does strongly typed language and weakly typed. String 10 was implicitly converted to number 10 since the operation was expecting an integer and vb acted weakly typed. Instant download best exam practice material 100% money back guarantee. A ref cursor can be weakly typed or strongly typed. In a statically typed language, type checking is performed at compile time. This chapter shows how plsql supports the sql commands, functions, and operators that let you manipulate oracle data. Understanding cursor types sql server microsoft docs.
Java,stored procedure,oracle,stored procedures and. A strong ref cursor type definition specifies a return type, but a weak definition does not. Most of these rules affect variable assignment, return values and function calling. Module module1 sub main dim a as string 10a system. A weakly typed ref cursor is one that does not declare the record type of the cursor it references and hence can be used to reference cursors of different types at different times. An expression whose value is passed to the dynamic select statement. What is difference between weak reference type and strong. It is worth mentioning the configured column name will act as the inclusive starting point for the employee object mapping. Because there is no type checking with a weak ref cursor, all such types are interchangeable.
Strong ref cursor types are less errorprone because plsql lets you associate a strongly typed cursor variable only with type compatible queries. Weak ref cursor types are more flexible because the compiler lets you associate a weakly typed cursor variable with any query. The difference is not about declaring types on variables. The last step creates a function that translates a weakly typed reference cursor into an aggregate table by using a pipelined function, as shown in the illustration. Cse 460598, asu the object model 41 strong typing strongly typed programming languages type conformance is strictly enforced i. Whats the difference between weak typing and dynamic.
Typing untyped weakly typed strongly typed typing is the. The reference cursor maintains a separate connection to the database to access the reference cursor. The cursor variable then acts as a pointer to the query or select thus opened. Help how to hide the cursor when the sentence finishes. The easiest way forward is to define a weakly typed ref cursor in a plsql package. Strong ref cursor types are less errorprone because plsql lets you associate a strongly typed cursor variable only with typecompatible queries weak ref cursor types are more flexible because you can associate a weakly typed cursor variable with any query. Rwdesigner flickr group post your photos to rwdesigner group on flickr. I always thought weakly typed, dynamic language would be a disaster.
Our source, who e xamined the software in great detail before it disappeared inside microsoft says it had a clever trick to ensure memory integrity that allowed it to handle weakly typed languages such as c and c a great advantage over the single language approach in java. Visit the open icon library and download thousands of icons from various authors. Note, as an alternative, the weaklytyped but less maintainable withspliton version can be used. Description this function takes an opened, parsed, and executed cursor and transformsmigrates it into a plsql manageable ref cursor a weaklytyped cursor that can be consumed by plsql native dynamic sqlswitched to use native dynamic sql. Cursor variables hold a reference to the context of the cursor defined by the cursor data type. Cursor variables can be declared within sql procedures using the declare statement. A weakly typed language has looser typing rules and may produce unpredictable results or may perform implicit type conversion at runtime. Java,stored procedure,oracle,stored procedures and java. However both vb and php amongst most popular languages in the last 2 decades fall into this category. It is statically typed, because you always have to declare your variables before you use them. Strongly typed and weakly typed languages java in general. In practice, weakly typed languages are usually dynamically typed. This gives greater flexibility, but it increases the likelihood of runtime errors because column mismatches are not picked up at compile time. Strong ref cursor types are less errorprone because plsql lets you associate a strongly typed cursor variable only with typecompatible queries.
Oracle jdbc extensions using java database connectivity. Weakly typed cursor variables are useful when you must store a result set with an unknown row definition. In a weakly typed language, variables dont have a type. The easiest way forward is to define a weakly typed ref cursor in a. However, it seems politically insensitive to use that language even though oracle published it as such. Its a bit more subtle than that and pace eric lippert, i think the term is reasonably welldefined. Weakly typed the return clause is omitted allowing the type to reference any return type. Realworld artists on deviantart join a group of realworld tools users.
This property is maintained in variables created of each type. Cursor variables can be stronglytyped or weaklytyped. Create a report based on ref cursor query using only a strongly typed ref cursor. Also the ability to infer types is gaining a lot of traction. This chapter has served as an overview of plsql and ref cursor stored procedures and their use in crystal. Weakly typed ref cursor the return clause is omitted from the ref cursor allowing the type to reference any return type. Different types of cursors in plsql oracle live sql.
The compiler cannot determine the types until it is ran, so care must be taken to ensure that the cursor result set is handled properly to avoid runtime errors. This is known as an associative array, and commonly called a plsql table by folks who predate the oraclei documentation that oracle would prefer we forget. Dynamically typed languages where type checking happens at run time can also be strongly typed. The set of rows returned by a select statement consists of all the rows that satisfy the. The following demonstrates how to read a plsql reference cursor in a php program. A strongly typed refcursor must hold a select statment whos returned rows match the type the cursor is defined to. Weak ref cursor types are more flexible because you can associate a weakly typed cursor variable with any query. A ref cursor is a weakly typed cursor type that identifies a cursor variable. Weak typing and dynamic typing are not necessarily opposites on the same spectrum. I took a different approach, probably not the most efficient but its easier to work with and you can not only remove the cursor but do whatever you desire when it finishes typing. A weakly typed cursor doesnt anchor the output of a query to a table or. Tech support scams are an industrywide issue where scammers trick you into paying for unnecessary technical support services. You can help protect yourself from scammers by verifying that the contact is a microsoft agent or microsoft employee and that the phone number is an official microsoft global customer service number. Difference between strongly and weakly typed languages.
Weak typing is contrasted with strong typing, and dynamic typing is contrasted with static typing. It is strongly typed, because a variable of type int will always hold int values. Operations in a relational database act on a complete set of rows. You can then fetch data from this cursor variable into local variables, or even pass that cursor variable to a nonpl. The fundamental difference between weak and strong reference type is decided by return clause of cursor type declaration. Php code to read a plsql reference cursor maclochlainns. The distinction is that in a stronglytyped language, every expression has a type which can be determined at compile time, and only operations appropriate to that type are allowed.
A variable can defined of the ref cursor type and then a query can be opened for it. Repeated calls to microsoft yielded no information about what has happened to the colusa. Having said that, these days i see more and more languages are strongly typed. A string literal, variable, or expression that represents a multirow select statement. It does compile successfully but at the same time throws an exception at runtime.
However, it seems politically insensitive to use that language even though oracle. Cursor moves when typing when i am typing, my cursor moves to other areas on the screen, and inserts text where it should not be. The difference between a strongly typed language and a weakly typed language is basically that a strongly typed language checks the type of a variable before performing an operation on it, whereas a weakly typed language does not. The main agenda of this post is to discuss cursor type weak and strong type. Weak ref cursor types are more flexible because you can associate a weakly typed cursor variable with any. This gives greater flexibility and has a dynamic nature, but it increases the likelihood of runtime errors because column mismatches are not picked up at compile time. One of the best ways to isolate an application from sql dependencies is to write a package of plsql functions that return the ref cursor type to the calling programs written in other host languages such as java or c. Registered users may also upload and publish their icons. Weakly typed article about weakly typed by the free. The good news is there are now several free utilities that you can download that will freeze the touchpad as soon as it detects you are typing. Strongly typed reference cursor maclochlainns weblog. The property of being strongly or weakly typed is defined when the data type is created. The following is an example of a weakly typed cursor variable declaration based on the builtin weakly typed cursor data type cursor.
980 11 1554 83 733 1554 1110 1421 180 1549 1226 846 110 720 250 1636 1123 345 1307 1082 1223 685 549 694 534 686 861 1218 1349 898 759 776 133 94 1158 99 621