multiple-databases
Differences
This shows you the differences between two versions of the page.
| Next revision | Previous revision Next revision Both sides next revision | ||
|
multiple-databases [2015/09/23 20:27] 127.0.0.1 external edit |
multiple-databases [2016/01/22 15:35] dmtolpeko [Configuring and Using Connections] |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| - | ====== Working with Multiple Databases in PL/HQL ====== | + | ====== Working with Multiple Databases in HPL/SQL ====== |
| - | PL/HQL allows you to access multiple databases simultaneously from a single PL/HQL script. | + | HPL/SQL allows you to access multiple databases simultaneously from a single HPL/SQL script. |
| ===== Why Multiple Databases? ===== | ===== Why Multiple Databases? ===== | ||
| Line 7: | Line 7: | ||
| Hadoop extends, not replaces a traditional data warehouse, so you have to work with different systems for different type of workloads. | Hadoop extends, not replaces a traditional data warehouse, so you have to work with different systems for different type of workloads. | ||
| - | Most SQL-on-Hadoop solutions are good for querying large volumes of data rather than transaction processing. Note that Hive stores its metadata is a separate database (MySQL, PostgreSQL, Oracle etc.). | + | Most SQL-on-Hadoop solutions are good for querying large volumes of data rather than transaction processing. Note that even Hive stores its own metadata is a separate database (MySQL, PostgreSQL, Oracle etc.). |
| When you use Hive or other SQL-on-Hadoop tool to query your data, you can use a RDBMS or NoSQL to: | When you use Hive or other SQL-on-Hadoop tool to query your data, you can use a RDBMS or NoSQL to: | ||
| Line 20: | Line 20: | ||
| Before you can work with multiple databases, you have to [[connections|configure connections]]. | Before you can work with multiple databases, you have to [[connections|configure connections]]. | ||
| - | PL/HQL connects to a database only when it executes the first SQL statement for this database, the tool does not connect to any database in advance. | + | HPL/SQL connects to a database only when it executes the first SQL statement for this database, the tool does not connect to any database in advance. |
| - | Once connected, PL/HQL holds and re-uses the connection until the script completes. | + | Once connected, HPL/SQL holds and re-uses the connection until the script completes. |
| ===== Default Connection ===== | ===== Default Connection ===== | ||
Page Tools
