![]() |
![]() |
QUERY/V Reference Manual: HP 3000 MPE/iX Computer Systems > Chapter 1 INTRODUCING QUERY/V![]() MODES OF ACCESS |
|
Each person using QUERY to access a data base must specify one of the 8 modes of access. The following table lists the capabilities you will have in each mode.
A data base can only be shared in certain situations or environments. The mode you specify must be acceptable for the environment already established by other IMAGE and QUERY users (if any) when you open the data base. Here is a summary of the acceptable environments:
Subsets of these environments are also allowed. For example, there may be all mode 6 users or all mode 8 users. There may also be one mode 1 user or all mode 5 users and so forth. If a mode 3 or mode 7 user is currently accessing the data base that you want to access, you must wait until that user either terminates their IMAGE or QUERY session or accesses a different data base. This is true any time you try to access a data base with a mode which is incompatible with other users accessing the same data base. Changing your mode of access may enable you to access the data base. When deciding which mode to use, you should consider the following:
Figure 1-3 “IMAGE/QUERY Environments” illustrates acceptable IMAGE/QUERY environments. Users at terminals can operate IMAGE or QUERY simultaneously. A single user indicates that only one user may specify that mode. Two users indicates that multiple users may specify that mode. Terminals indicate the modes which are incompatible with the current environment. The capability of each user is abbreviated as follows: F = find, R = replace, A = add, D = delete. Opening the data base in modes 1 through 4 allows data base modifications to be logged to a log file and subsequently recovered if there is a system failure. If the data base administrator has enabled the data base for logging, certain requirements of the logging system must be met before the data base can be accessed in modes 1 through 4. These requirements are the responsibility of the data base administrator and console operator, and are discussed in the IMAGE Reference Manual. If any of these requirements are not satisfied, an IMAGE error message is returned. |