Có 40+ tài liệu thuộc chủ đề "Oracle cơ bản"
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Does a REF sound a lot like a foreign key? While there are important differences between REFs and foreign keys (see Table 18.2), Oracle actually claims that REFs, are "more reliable and persistent". Table 18.2: Chief Differences between Foreign Keys and REFs. Restricts updates of the parent key when children exist?. Can cascade deletions of the parent to child (objects)?....
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Oracle PL/SQL. Chapter 19 Next: 19.2 Creating the New Collections. 19.1 Types of Collections. Like nested tables, they can be used in PL/SQL and in the database. Table 19.1: Storing a Nonatomic Column of Dependents in a Table of Employees Id (NUMBER) Name (VARCHAR2) Dependents_ages (Dependent_birthdate_t). with the rest of the table's data.. Table 19.2 illustrates many of the additional...
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Object Views. Object Views 19.8 Collections. Chapter 20 Next: 20.2 INSTEAD OF Triggers. Example: Using Object Views INSTEAD OF Triggers. Syntax for Object Views. Differences Between Object Views and Object Tables Not All Views with Objects Are Object Views. Object Views Housekeeping. To allow established applications to take advantage of the new object features over time, Oracle8 provides object views....
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Oracle PL/SQL. Typically, whatever is a program that interacts with the external environment: sending email, polling or controlling hardware, or invoking the C library functions that PL/SQL lacks. What we need from Oracle is a fast, reliable way of calling out to operating system commands or functions from within PL/SQL. (There is no such thing as a procedure in C.)...
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Can I say the same thing about the next version of the loop?. recommend that in order to further distinguish parameters from other PL/SQL identifiers you include the parameter mode right in the name of the formal parameter.. An OUT parameter passes a value out of the module, but its value cannot be referenced in the module. As a suffix,...
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I can now call this procedure using the default value of NET, since the Oracle Forms version of the procedure always passes a value to the stored procedure version:. (In Version 7.1 of the Oracle Server, by the way, you will be permitted to use default values in remote procedure calls.). This situation with Oracle Server Version 7 reinforces one...
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After examining the function, it was clear to me that the only way it could return a NULL was if one of the inputs was NULL. I performed a walk-through of the code and could not identify how any of the other two variables could be NULL.. After two hours of this nonsense, I finally said to myself, "Well, you...
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If they were the only tuning steps you took (or the only ones left to take) in your PL/SQL programs, I doubt that you would notice a difference. SQL blocks will contribute to a more efficient PL/SQL layer in your application.. With the exception of cursor variables, PL/SQL passes arguments by value, instead of reference, in the parameter lists of...
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PROCEDURE DBMS_JOB.INTERVAL (job IN BINARY_INTEGER, interval IN VARCHAR2);. PROCEDURE DBMS_JOB.NEXT_DATE (job IN BINARY_INTEGER, next_date IN DATE);. PROCEDURE DBMS_JOB.REMOVE (job IN BINARY_INTEGER);. PROCEDURE DBMS_JOB.RUN (job IN BINARY_INTEGER);. PROCEDURE DBMS_JOB.USER_EXPORT (job IN BINARY_INTEGER, mycall OUT VARCHAR2);. PROCEDURE DBMS_JOB.WHAT (job IN BINARY_INTEGER, what IN VARCHAR2);. PROCEDURE DBMS_LOB.APPEND (dest_lob IN OUT BLOB, src_lob IN BLOB);. PROCEDURE DBMS_LOB.APPEND. PROCEDURE DBMS_LOB.COPY. PROCEDURE DBMS_LOB.ERASE. PROCEDURE DBMS_LOB.FILECLOSE (file_loc...
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PROCEDURE DBMS_TRANSACTION.SAVEPOINT;. PROCEDURE DBMS_TRANSACTION.USE_ROLLBACK_SEGMENT (rb_name VARCHAR2);. Any PL/SQL using this procedure must be coded to ensure that the transaction is attempted again in the event of a discrete transaction failure.[3] The specification is:. PROCEDURE DBMS_TRANSACTION.BEGIN_DISCRETE_TRANSACTION;. PURGE_MIXED procedure.[4] The specification is:. PROCEDURE DBMS_TRANSACTION.PURGE_MIXED (xid VARCHAR2);. C.15.16 The. PROCEDURE DBMS_TRANSACTION.PURGE_LOST_DB (xid VARCHAR2);. C.15.17 The. FUNCTION DBMS_TRANSACTION.LOCAL_TRANSACTION_ID (create_transaction BOOLEAN. FUNCTION DBMS_TRANSACTION.STEP_ID RETURN VARCHAR2;....
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PURGE_MIXED procedure.[4] The specification is:. PROCEDURE DBMS_TRANSACTION.PURGE_MIXED (xid VARCHAR2);. C.15.16 The. C.15.17 The. Next: C.16. DBMS_UTILITY. C.14 DBMS_SQL Book Index C.16 DBMS_UTILITY. Next: C.17 UTL_FILE. C.16 DBMS_UTILITY. The DBMS_UTILITY package includes several utility modules you might find useful when managing objects in the database.. C.16.1 The. PROCEDURE DBMS_UTILITY.ANALYZE_SCHEMA (schema VARCHAR2,. C.16.2 The. PROCEDURE DBMS_UTILITY.COMMA_TO_TABLE (list IN VARCHAR2,. C.16.3 The. PROCEDURE...
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Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. While every precaution has been taken in the preparation of this book, the publisher and authors assume no responsibility for errors or omissions, or for damages resulting from the use of the information con- tained herein.. What’s This Replication Stuff Anyway? 5. A...
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If this option is omitted, the server ID will be read from the configuration file of the server. A Brief Introduction to the Binary Log | 27. The name and password of the replication user will be stored in the server so that when slaves are connected, the class can look up the replication username.. A Brief Introduction to the...
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transaction, the server writes all the statements that are part of the transaction to the binary log as a single unit. Each statement executed for a transaction is placed in the transaction cache, and the contents of the transaction cache are then copied to the binary log and emptied when the transaction commits.. These statements are considered transactional but include...
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You will lose any changes that were made on the master but not yet sent to the standby.. We will cover how to handle the recovery of the master in this case separately.. If the standby is behind one of the slaves, you shouldn’t use the standby as the new master, since the slave knows more than the standby. instead...
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Since the master is ahead of the slave, it is possible that the change has not reached the slave yet, so a query to the slave will then find the cart empty. The problem needs to be handled in different ways depending on whether there are any relay slaves between the master and the slave.. After fetching the binlog position...
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Stop the I/O thread of the slave using STOP SLAVE IO_THREAD . The binlog-format option can be set to use one of the following modes:. switch to row-based replication if the statement is considered unsafe through one of the criteria we have discussed in this chapter.. The statement calls any of the following:. The Table_map event maps a table ID...
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Let’s examine some of the basic reporting tools first.. Figure 7-24 shows an example of the Windows Experience report.. A low score in any of the categories can indicate a performance issue. click the link “Generate a system health report” at the bottom of the dialog. Click Advanced Tools and select the link “Generate a system health report” at the...
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For example, after each EXPLAIN , check the value of the variable. You can update the key distribution for MyISAM and InnoDB tables. A typical execution of the command is shown in Example 8-11. You can see the status of your indexes using the SHOW INDEX command. A sample of the output of the film table is shown in Example...
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Monitoring Commands for the Slave. The SHOW SLAVE STATUS command displays information about the slave’s binary log, its connection to the server, and replication activity, including the name and offset position of the current binlog file. This tells you the current status of the I/O thread. The information displayed about the master connection includes the current hostname of the master,...