import org.hsqldb.FunctionCustom; //导入依赖的package包/类
/**
 * Retrieves a comma-separated list of math functions available with
 * this database.  These are the Open /Open CLI math function names used in
 * the JDBC function escape clause.
 *
 * @return the list of math functions supported by this database
 * @exception SQLException if a database access error occurs
 */
public String getNumericFunctions() throws SQLException {
    return StringUtil.getList(FunctionCustom.openGroupNumericFunctions,
                              ",", "");
}
 

import org.hsqldb.FunctionCustom; //导入依赖的package包/类
/**
 * Retrieves a comma-separated list of string functions available with
 * this database.  These are the  Open Group CLI string function names used
 * in the JDBC function escape clause.
 *
 * @return the list of string functions supported by this database
 * @exception SQLException if a database access error occurs
 */
public String getStringFunctions() throws SQLException {
    return StringUtil.getList(FunctionCustom.openGroupStringFunctions,
                              ",", "");
}
 

import org.hsqldb.FunctionCustom; //导入依赖的package包/类
/**
 * Retrieves a comma-separated list of system functions available with
 * this database.  These are the  Open Group CLI system function names used
 * in the JDBC function escape clause.
 *
 * @return a list of system functions supported by this database
 * @exception SQLException if a database access error occurs
 */
public String getSystemFunctions() throws SQLException {
    return StringUtil.getList(FunctionCustom.openGroupSystemFunctions,
                              ",", "");
}
 

import org.hsqldb.FunctionCustom; //导入依赖的package包/类
/**
 * Retrieves a comma-separated list of the time and date functions available
 * with this database.
 *
 * @return the list of time and date functions supported by this database
 * @exception SQLException if a database access error occurs
 */
public String getTimeDateFunctions() throws SQLException {
    return StringUtil.getList(FunctionCustom.openGroupDateTimeFunctions,
                              ",", "");
}