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What is the difference between execute(String sql) and update(String sql) in JdbcTemplate?
If my statement is a straight CRUD and not an object creation DDL (as the execute javadoc implies), does it make sense to use execute vs the seemingly more lightweight update?
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NamedParameterJdbcTemplate class is a template class with a basic set of JDBC operations, allowing the use of named parameters rather than traditional '?' placeholders. This class delegates to a wrapped JdbcTemplate once the substitution from named parameters to JDBC style '?' placeholders is done at execution time.
JdbcTemplate is class which will help us to query the database. update() is a method provided by JdbcTemplate , which is used to update the java object into the database. update() takes 2 parameters, sql_query and parameters.
The spring jdbctemplate internally invokes the java. sql executeUpdate method, which can execute an insert , update, delete or ddl statements.
ResultSetExtractor is suppose to extract the whole ResultSet (possibly multiple rows), while RowMapper is feeded with row at a time. Most the time, ResultSetExtractor will loop the ResultSet and use RowMapper , snippet example of Spring RowMapperResultSetExtractor : List<T> results = (this.
The method execute(String sql) returns void if a call of the method succeeds without errors. (see execute(..) JavaDoc). As for plain JDBC, it should/can be used to define database schema elements (DDL), for instance with CREATE TABLE... statements.
By contrast, update(String sql) is typically used for DML statements which correspond to SQL INSERT/UPDATE/DELETE operations. In these cases, in which data are manipulated, from a programmer's perspective it is important to know how many rows have been added/changed/deleted by the respective DML operation.
For this reason, the update(...) method returns a non negative int value to let you know:
Returns: the number of rows affected
As the JavaDoc indicates by using the term "typically" in its description, you could, however, use execute(String sql) to manipulate data without the need to use the returned int value. In theory, and for some DBMS implementations, this call could be some nanoseconds quicker, as no return value needs to be transferred.
Yet, from my personal and a programmer's perspective, you should use both operations with the difference between DDL vs. DML statements in mind, as by its nature update signals a data manipulation operation being conducted.
Hope, it helps.
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