Mercurial > hg > monetdb-java
changeset 946:b21578cf909f
Remove info on URL Format, Use and Notes and tips. These have been moved to the web documentation page.
| author | Martin van Dinther <martin.van.dinther@monetdbsolutions.com> |
|---|---|
| date | Thu, 09 Jan 2025 19:03:47 +0100 (2 months ago) |
| parents | 4dd3bc7162f6 |
| children | bd4964f4656e |
| files | release.md |
| diffstat | 1 files changed, 2 insertions(+), 142 deletions(-) [+] |
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--- a/release.md +++ b/release.md @@ -2,7 +2,6 @@ RELEASE NOTES ============= MonetDB JDBC driver version 3.3 (Liberica) -<br> Release date: 2023-02-23 The Java Database Connectivity (JDBC) API provides universal data access from @@ -14,145 +13,6 @@ For more information see https://www.mon The latest MonetDB JDBC driver can be downloaded from https://www.monetdb.org/downloads/Java/ -The sources for this JDBC driver and related Java programs can be found at: -https://dev.monetdb.org/hg/monetdb-java/file/tip - - -URL Format ----------- - -The MonetDB JDBC connection URL format is: - -<pre> -jdbc:<b>monetdb</b>://[<host>[:<port>]]/<databasename>[?<properties>] (not encrypted) -OR -jdbc:<b>monetdbs</b>://[<host>[:<port>]]/<databasename>[?<properties>] (encrypted) - -where <properties> are &-separated: prop1=value1[&prop2=value2[&prop3=value3...]] -</pre> - -The second form (monetdbs) is for creating a TLS-protected connection. TLS (Transport Layer Security) -is the mechanism that is also used for HTTPS. - -Property keys and values support percent-escaped bytes. For example, the -password 'chocolate&cookies' can be passed as follows: `jdbc:monetdb:///demo?user=me&password=chocolate%26cookies`. - -Note: MonetDB-Java version 3.3 and earlier did not support percent-escapes. -If your password contains percent-characters, these must now be encoded as `%25`. - -Supported connection properties are: - -| Property | Default | Notes | -| ----------------------------------------- | ------- | --------------------------------------------------- | -| user=<login name> | - | required | -| password=<secret value> | - | required | -| so_timeout=<time in milliseconds> | - | | -| treat_clob_as_varchar=<bool> | true | | -| treat_blob_as_binary=<bool> | true | | -| language=<sql or mal> | sql | | -| replysize=<nr of rows> | 250 | -1 means fetch everything at once | -| autocommit=<bool> | true | | -| schema=<schema name> | - | initial schema to select | -| timezone=<minutes east of UTC> | system | | -| debug=true | false | | -| logfile=<name of logfile> | | | -| hash=<SHA512, SHA384, SHA256 or SHA1> | | | -| cert=<path to certificate> | - | TLS certificate must be in PEM format | -| certhash=sha256:<hexdigits and colons> | - | required hash of server TLS certificate in DER form | - - -Booleans <bool> can be written as 'true', 'false', 'yes', 'no', 'on' and 'off'. Property 'fetchsize' is accepted as an alias of 'replysize'. - -Client authentication (Mutual TLS, or MTLS) is not yet supported. - -When the properties 'treat_clob_as_varchar' and 'treat_blob_as_binary' are enabled, - -The properties 'treat_clob_as_varchar' and 'treat_blob_as_binary' control which -type is returned by ResultSetMetaData.getColumnType(int) for CLOB and BLOB columns. -When 'treat_clob_as_varchar' is enabled, Types.VARCHAR is returned instead of Types.CLOB -for CLOB columns. When 'treat_blob_as_binary' is enabled, Types.VARBINARY is returned instead -of Types.BLOB for BLOB columns. -This will cause generic JDBC applications such as SQuirrel SQL and DBeaver to use -the more efficient '#getString()' and '#getBytes()' API rather than '#getClob()' and -'#getClob()'. -These properties are enabled by default since MonetDB-Java version 3.0. - - -Use ---- - -See also: https://www.monetdb.org/Documentation/SQLreference/Programming/JDBC +Documentation on the MonetDB JDBC driver is avaliable from +https://www.monetdb.org/documentation/user-guide/client-interfaces/libraries-drivers/jdbc-driver/ -The MonetDB JDBC driver class name is `org.monetdb.jdbc.MonetDriver`. -This has been changed as of release 3.0 (monetdb-jdbc-3.0.jre8.jar). -The old driver class (nl.cwi.monetdb.jdbc.MonetDriver) has been deprecated -since 12 Nov 2020 and has been removed in release 3.4 (monetdb-jdbc-3.4.jre8.jar). - - -Notes and tips --------------- - -- After creating a Connection object check for SQLWarnings via conn.getWarnings(); - -- Close JDBC ResultSet, Statement, PreparedStatement, CallableStatement and - Connection objects immediately (via close()) when they are no longer needed, - in order to release resources and memory on the server and client side. - Especially ResultSets can occupy large amounts of memory on the server and - client side. - -- By default the ResultSets created by methods in DatabaseMetaData - which return a ResultSet (such as dbmd.getColumns(...)) are - TYPE_SCROLL_INSENSITIVE, so they cache their ResultSet data to - allow absolute, relative and random access to data rows and fields. - To free heap memory and server resources, close those ResultSets - immediately when no longer needed. - -- By default the ResultSets created by stmt.executeQuery(...) or - stmt.execute(...) are TYPE_FORWARD_ONLY, to reduce the potentially large - amount of client memory needed to cache the whole ResultSet data. - -- When you need to execute many SQL queries sequentially reuse the Statement - object instead of creating a new Statement for each single SQL query. - Alternatively you can execute the SQL queries as one script (each SQL query - must be separated by a ; character) string via stmt.execute(script), - stmt.getResultSet() and stmt.getMoreResults(). - Or you can use the batch execution functionality, see stmt.addBatch() and - stmt.executeBatch() methods. - -- The fastest way to retrieve data from a MonetDB ResultSet is via the - getString(int columnIndex) method, because internally all data - values (of all types) are stored as Strings, so no conversions are needed. - -- Avoid using rs.getObject() as it will need to construct a new Object for - each value, even for primitive types such as int, long, boolean. - -- Avoid using rs.getClob(). Instead use getString() for all CLOB - columns, which is much faster and uses much (3 times) less memory. - -- Avoid using rs.getBlob(). Instead use getBytes() to get a byte array - or use getString() to get a string containing hex pairs, for all BLOB - columns. These methods are much faster and use much less memory. - The getString() is the fastest way as no conversions are done at all. - The getBytes() will need to convert the hex char string into a new bytes[]. - -- Try to avoid calling "rs.get...(String columnLabel)" methods inside the - while(rs.next()) {...} loop. Instead resolve the columnLabels to column - numbers before the loop via method "int findColumn(String columnLabel)" - and use the int variables with the rs.get...(int columnIndex) methods. - This eliminates the call to findColumn(String columnLabel) for - each value of every column for every row in the ResultSet. - See also the example Java JDBC program on: - https://www.monetdb.org/Documentation/SQLreference/Programming/JDBC - -**WARNING**: - The current implementation of the MonetDB JDBC driver is *NOT* - multi-thread safe. If your program uses multiple threads concurrently on - the same Connection (so one MapiSocket), this may lead to incorrect behavior - and results (due to race conditions). - You will need to serialize the processing of the threads in your Java program. - Alternatively you can use a separate JDBC Connection for each thread. - -Note: as of version 3.0 (monetdb-jdbc-3.0.jre8.jar) we compile all - the java sources to target: Java SE 8 (profile compact2), so - you need a JRE/JDK JVM of version 8 or higher to use it. -