TAILIEUCHUNG - ORACLE8i- P25

ORACLE8i- P25: We want information information.” Possibly you recognize these words as the primary interest of a somewhat clandestine group, and as told by a character called Number 2 to Patrick McGoohan’s character Number 6 (in the old TV show The Prisoner). Indeed, in this day, information is king, and the speedy, accurate, and reliable retrieval of this information is paramount. | 958 I CHAPTER 21 ORACLE8i DATABASE SECURITY context package user sign-on context package seems like a more appropriate name. The context area is an area of private memory that is unique to every session connected to the database. You will create placeholders in this memory area to store some values that are set at logon. Later in the process you will read the context memory area and retrieve these stored memory areas for use. This is an optional step. You could define the context area every time the user accesses the object but this approach is faster because you do these checks only once. You place values into the context area by creating a package or function that is called each time users log on to the database. For this project you will store the user s assigned security level into a context variable whenever the user logs in. This way you can quickly retrieve this security value from the context area when you need it. This saves multiple trips to the security table to look up the security ID each time you need that value. Before you can use a context namespace you must first create the context namespace which needs to be done only once for each specific context area. The context namespace is created using the CREATE CONTEXT command or you can use CREATE OR REPLACE CONTEXT if you prefer . When you create the context namespace you define the package that will be used to set the values to be stored in the context namespace. Typically when you create the context the associated package will not have been created yet and that s okay. You will create that package next. NOTE Creating the context namespace is similar to programming with a pointer. You first create the pointer and then you allocate memory to it. The same is true with a context. You first create the context and then the context setting package allocates what is to be stored to the context. Okay so all comparisons have limitations After you have created the context area you will use the

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