how to use dblink in oracle sql

How can I view the current number of connections in Oracle? You only need to use the following SQL statement to query it. Select * from V $ session where username is not null Select username, count (username) from V $ session where username is not null group by username # view the number of connections of different users Select count (*) from V $ session #

Ordered prompts to force Oracle to join tables in the order in which they appear in the FROM clause. By ordered hints, you can avoid table connection evaluations during the CBO SQL parsing process, thus avoiding Oracle generating incorrect execution plans or forcing Oracle to execute in the way we specify. In many ca

The following article mainly introduces how to use Oracle SQL statements to convert between systems. This article uses the actual code to implement conversions between systems. Based on the actual example, you can change the base number of power to the corresponding base number. The following describes Oracle

views to obtain the absolute path of the trace file of a Sid. In 11g, Oracle added a view v $ diag_info for us. SQL>Select * FromV $ diag_info; Inst_id name value -- ----------------------------------------------------------------------------------------------------------------------------------- 1 Diag enabled true 1 ADR Base E: \ app \User 1 ADR home E: \ app \ User \ Diag \ RDBMS \ orcl

Tested how to use wrap to encrypt self-written SQL scripts You can encrypt the processes, functions, packages, and other SQL scripts you write to prevent others from reading your code. This encryption method is irreversible and cannot be decrypted back to the original content after encryption. Syntax: Wrap INAME =.../../some_

SQL * Loader is a tool used to import external data from Oracle databases. it is similar to the Load tool of DB2, but has more options. It supports variable loading modes, optional loading and multi-Table loading. How to use SQL * Loader We can use the sqlldr tool of

------------------------------------------------------------------------0 | --> 1871 |> 512 |> 343 |> 194 |> 195 |> 206 |> 507 |-> 107NOW: 8 | ---------> 6829 | -----------------> 134210 | ------------------------> 185411 | -----------------> 129212 | ------------------> 141613 | ---------------> 118014 | ----------------> 121715 | --------------------> 157316 | -----------------------> 178517 | -------------------> 146918 | -------------------------> 189219 | -------------------------> 190720 |

Looking at the fat Oracle client on my computer, I almost never used anything like the Enterprise Manage Console. Its existence is a waste of my computer space. So I checked on the Internet to see if I could unmount the ORACLE client and use PL/SQL normally. It turns out that this method is available (I did my research

This article describes how to use SQL loader to insert data from an Oracle database into an Excel file. Implementation purpose: Insert data from an Excel file into an Oracle database Implementation steps: 1. Open Microsoft Excel 2000 2, file (F) → new (N) → workbook → 3, after the input data, save for Test.xls, 4

This article provides an indirectExcelData Import inOracleMethod: UseSQL ServerClose relationships with Excel. in SQL Server, use the OpenDataSource method to read Excel and spell the data into an oracle-compliant SQL statement. Run the following code in SQL server: SEL

What should you write if you need to use SQL recursive statements in an Oracle database? Here's an example of a SQL recursive statement used in Oracle for your reference. Example: Copy Code code as follows: PID ID A b A C A E b B1 b B2 C C1 E E1 E E3 D D

Cited:To illustrate this, a score table is created, as shown in:Comparison:1, in SQL, these two functions we can only use case, the code and the results are as follows:Select Name,Case SubjectWhen ' Chinese ' then 1When ' math ' then 2When ' English ' then 3--else 3End as ' account code 'From ResultsSimilarly, we can use case to implement row to column, the code

Use the Hibernate framework to generate executable SQL statements for hql-Oracle DialectIntroduction: Why is this requirement derived from the company's project requirements? The company's project uses java's struts2 + spring2.5 + oracle middleware tuxedo. The database uses Oracle