Also, in the return clause of a ref cursor type definition, you can use %rowtype to specify a record type that represents a row returned by a strongly not weakly typed cursor variable. Plsql reference type can be of explicitimplicit type and cursor variable. There are some situations where weakly typed objects are needed or useful, such as a weakly typed cursor variable that can be used for any query. A weakly typed cursor variable one without a return type previously declared within the current scope. Weak ref cursor types are more flexible because the compiler lets you associate a weakly typed cursor variable with any query. Java,stored procedure,oracle,stored procedures and java. The main agenda of this post is to discuss cursor type weak and strong type.
A strong typed ref cursor has a return type defined when the ref cursor itself is declared in plsql. Java,stored procedure,oracle,stored procedures and java,result set. Strong ref cursor types are less errorprone because plsql lets you associate a strongly typed cursor variable only with typecompatible queries. Im attempting to do something that i assume would be a common requirement. The fundamental difference between weak and strong reference type is decided by return clause of cursor type declaration. Cursor variables can be either weakly typed, which are more flexible, or strongly typed, which provide greater type safety. 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. However, it seems politically insensitive to use that language even though oracle published it as such. When a refcursor is defined with a return type, it is called as a strongly typed static refcursor. Different types of cursors in plsql oracle live sql.
Cursor attributes and cursor variable usage weakly typed. The first block assigns a strongly typed cursor variable to another with the same datatype definition. Types of cursors available in oracle plsql dzone database. Whenever cursor executed inside the plsql block memory allocateddeallocated automatically based on the type of cursor. This identifies an explicit cursor previously declared within the current scope. Oracle database tips by donald burlesonfebruary 17, 2015. Packages are used in plsql for partitioning functionality. Oracle jdbc extensions using java database connectivity. Create a report based on ref cursor query using only a strongly typed ref cursor. 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. Cursor is used to access the result set present in the memory. Some really nice aspects of cursor variables, demonstrated in this package. Weakly typed or strongly typed ref cursor 24208 jul 19, 2005 7. In addition to providing the performance improvements described in earlier sections, cursor functionality now extends beyond queries, and it is.
How do i pass rec, which is a record of a weakly typed cursor, to a procedure for processing. The cursor variable then acts as a pointer to the query or select thus opened. A strong ref cursor type definition specifies a return type, but a weak definition does not. Weak ref cursor types are more flexible because you can associate a weakly typed cursor variable with any. A ref cursor that specifies a specific return type. A ref cursor is a user defined type allows you to declare the cursor variable which is. So, the answer to your question about how to use strongly typed ref cursor in dynamic sql is that you dont. Returning a jdbc result set from an oracle stored procedure. However, that said i fail to see why you having to select in one stored procedure, to put the data into a global temporary table. 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. An expression whose value is passed to the dynamic select statement. Weakly typed or strongly typed ref cursor oracle community. Local plsql cursor variables are instantiated when you enter a block or subprogram and cease to exist when you exit.
Postgresql, for example, also supports ref cursors, so if you want portable java code, be sure not to use the oracle specific classes. A string literal, variable, or expression that represents a multirow select statement. Ref cursors can be further categorized in 2 parts 1 strongly typed ref cursor 2 weakly typed ref cursor when a return type is included while defining ref cursor it called strongly typed ref. I dont want to define a cursor and a type for the record of this type. However, only ref cursor without return type can be opened by an embedded dynamic open statement. Cursors with a defined return type are strongly typed. The second block assigns a strongly typed cursor variable to a weakly typed cursor variable. That is the number and type of the columns have to match though not the column names. Weak types can refer to any cursor, and so are much more flexible. Ask tom question on using ref cursor oracle ask tom. This gives greater flexibility, but it increases the likelihood of runtime errors because column mismatches are not picked up at compile time. Weakly typed the return clause is omitted allowing the type to reference any return type.
This loadthentransform strategy also provides a natural checkpointing scheme to the. Oracle plsql tips by boobal ganesan this is an excerpt from the book advanced plsql. Types of cursors available in oracle plsql heres a breakdown of the various pointers to sql result sets you can implement in your code. Weakly typed ref cursor the return clause is omitted from the ref cursor allowing the type to reference any return type. Currently, cursor variables are subject to several restrictions. 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.
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. 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. The key difference is you can only assign queries that match the return type to a strong cursor. How to execute an oracle procedure with an out cursor. Run operations using ref cursors in oracle database using. A ref cursor is a weakly typed cursor type that identifies a cursor variable. Takes an opened, parsed, and executed cursor by open, parse, and execute and transforms or migrates it into a plsql manageable ref cursor a weakly typed cursor that can be consumed by plsql native dynamic sql and switched to use native dynamic sql. The first block provides an example of a strongly typed cursor variable, while the following two examples are examples of weakly typed cursor variables.
The compiler cannot determine the types until it is ran, so care must be taken to ensure that the cursor result set is. Strong ref cursor types are less errorprone because plsql lets you associate a strongly typed cursor variable only with type compatible queries. This identifies a plsql strongly not weakly typed cursor variable previously declared within the current scope. Strong plsql ref cursors oracle consulting, oracle. A weakly typed ref cursor has a return type that is dependant on the sql statement it executes, i. In the return clause of a ref cursor type definition, you can use %rowtype to specify a record type that represents a row returned by a strongly not weakly typed cursor variable, as follows. This identifies a database table or view that must be accessible when the declaration is elaborated. For more information about how to invoke procedures and functions by using the wcf service model, see invoke functions and procedures in oracle database using the wcf service model. If a returntype is specified, this ref cursor type is strongly typed. In contrast to a strong typed ref cursor, a weak typed ref cursor has no return type defined, meaning that a weak typed ref cursor can refer to a query work area of any type. Defining cursor variables ref cursor return clause. The plsql statement that you use in the report as the data source for the query might look something like this.
Weak ref cursor types are more flexible because you can associate a weakly typed cursor variable with any query. The easiest way forward is to define a weakly typed ref cursor in a plsql package. A variable can defined of the ref cursor type and then a query can be opened for it. We are free to use this ref cursor type as parameters for our subroutines and return type for the functions without needing to create them in a package specification, as it is already done by oracle for us. Execute cursor and transforms or migrates it into a plsqlmanageable ref cursor a weaklytyped cursor that can be consumed by plsql native dynamic sql. Cursoris a memory object that will be stored inside your ram. Ref cursor can be passedreturned to another plsql routine function or procedure or even can be returned to client from the oracle database server. What is difference between weak reference type and strong.
Tim esten supports plsql data types and the interactions between plsql data types, timesten data types, and client application program data types. A weakly typed cursor doesnt anchor the output of a query to a table or. In the example above, a weakly typed cursor was used. Returns value of a named variable for a given cursor. To understand what the problem is you should investigate what strong typed and weak typed refcursors are. Oracle dbms has no builtin tools to put refcursor results into grid. As the oracle database has evolved over time, so has the humble cursor.
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