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@ -172,19 +172,23 @@ |
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1.4) What non-unix ports are available? |
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Client |
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It is possible to compile the libpq C library, psql, and other |
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interfaces and binaries to run on MS Windows platforms. In this case, |
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the client is running on MS Windows, and communicates via TCP/IP to a |
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server running on one of our supported Unix platforms. A file |
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win31.mak is included in the distribution for making a Win32 libpq |
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library and psql. |
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library and psql. PostgreSQL also communicates with ODBC clients. |
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Server |
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The database server can run on Windows NT and later using Cygwin, the |
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Cygnus Unix/NT porting library. See pgsql/doc/FAQ_MSWIN in the |
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distribution. The database server does not run on MS Windows 9X |
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because Cygwin does not support the required features on those |
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platforms. We have no plans to do a native port to any Microsoft |
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platform. |
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distribution or the MS Windows FAQ on our web site. The database |
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server does not run on MS Windows 9X because Cygwin does not support |
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the required features on those platforms. We have no plan to do a |
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native port to any Microsoft platform. |
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1.5) Where can I get PostgreSQL? |
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@ -310,8 +314,7 @@ |
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key referential integrity, and sophisticated locking. We have |
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some features they don't have, like user-defined types, |
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inheritance, rules, and multi-version concurrency control to |
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reduce lock contention. We don't have outer joins, but are |
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working on them. |
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reduce lock contention. |
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Performance |
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PostgreSQL runs in two modes. Normal fsync mode flushes every |
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@ -759,7 +762,7 @@ Maximum number of indexes on a table? unlimited |
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4.14) In a query, how do I detect if a field is NULL? |
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You test the column with IS NULL and IS NOT NULL. |
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You test the column with IS NULLIS NOT NULL. |
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4.15) What is the difference between the various character types? |
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@ -896,9 +899,13 @@ BYTEA bytea variable-length byte array (null-safe) |
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Depending on your shell, only one of these may succeed, but it will |
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set your process data segment limit much higher and perhaps allow the |
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query to complete. This command applies to the current process, and |
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all subprocesses created after the command is run. If you are having a |
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problem with the SQL client because the backend is returning too much |
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data, try it before starting the client. |
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all subprocessesHTML & CSS specifications are available from |
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http://www.w3.org/ To learn more about Tidy see |
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http://www.w3.org/People/Raggett/tidy/ Please send bug reports to Dave |
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Raggett care of Lobby your company to join W3C, see |
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http://www.w3.org/Consortium created after the command is run. If you |
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are having a problem with the SQL client because the backend is |
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returning too much data, try it before starting the client. |
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4.20) How do I tell what PostgreSQL version I am running? |
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@ -941,10 +948,18 @@ SELECT * |
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4.24) How do I do an outer join? |
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PostgreSQL 7.1 and later supports outer joins. In previous releases, |
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outer joins can be simulated using UNION and NOT IN. For example, when |
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joining tab1 and tab2, the following query does an outer join of the |
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two tables: |
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PostgreSQL 7.1 and later supports outer joins. Here is an example: |
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SELECT * |
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FROM t1 LEFT OUTER JOIN t2 USING (col); |
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This will join t1.col to t2.col, and return any unjoined rows in t1 |
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with NULL values for t2 columns. A RIGHT join would return unjoined |
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rows of table t2. A FULL join would return unjoined rows from t1 and |
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t2. The word OUTER is optional and is assumed in LEFT, RIGHT, and FULL |
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joins. Ordinary joins are called INNER joins. |
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In previous releases, outer joins can be simulated using UNION and NOT |
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IN. For example, when joining tab1 and tab2, the following query does |
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an outer join of the two tables: |
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SELECT tab1.col1, tab2.col2 |
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FROM tab1, tab2 |
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WHERE tab1.col1 = tab2.col1 |
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