Check precision for FLOAT data type and describe it in documentation

h2/src/docsrc/help/help.csv

@@ -2412,10 +2412,11 @@ DECIMAL(20, 2)
 "
 
 "Data Types","DOUBLE Type","
-{ DOUBLE [ PRECISION ] | FLOAT | FLOAT8 }
+{ DOUBLE [ PRECISION ] | FLOAT [ ( precisionInt ) ] | FLOAT8 }
 ","
 A floating point number. Should not be used to represent currency values, because
 of rounding problems.
+If precision value is specified for FLOAT type name, it should be from 25 to 53.
 
 Mapped to ""java.lang.Double"".
 ","
@@ -2423,10 +2424,11 @@ DOUBLE
 "
 
 "Data Types","REAL Type","
-{ REAL | FLOAT4 }
+{ REAL | FLOAT ( precisionInt ) | FLOAT4 }
 ","
 A single precision floating point number. Should not be used to represent currency
 values, because of rounding problems.
+Precision value for FLOAT type name should be from 0 to 24.
 
 Mapped to ""java.lang.Float"".
 ","

h2/src/main/org/h2/command/Parser.java

@@ -4446,6 +4446,18 @@ public class Parser {
                 }
                 read(")");
             }
+        } else if (dataType.type == Value.DOUBLE && original.equals("FLOAT")) {
+            if (readIf("(")) {
+                int p = readPositiveInt();
+                read(")");
+                if (p > 53) {
+                    throw DbException.get(ErrorCode.INVALID_VALUE_SCALE_PRECISION, Integer.toString(p));
+                }
+                if (p <= 24) {
+                    dataType = DataType.getDataType(Value.FLOAT);
+                }
+                original = original + '(' + p + ')';
+            }
         } else if (dataType.type == Value.ENUM) {
             if (readIf("(")) {
                 java.util.List<String> enumeratorList = new ArrayList<>();

h2/src/test/org/h2/test/scripts/datatypes/double.sql

@@ -2,3 +2,31 @@
 -- and the EPL 1.0 (http://h2database.com/html/license.html).
 -- Initial Developer: H2 Group
 --
+
+CREATE TABLE TEST(D1 DOUBLE, D2 DOUBLE PRECISION, D3 FLOAT, D4 FLOAT(25), D5 FLOAT(53));
+> ok
+
+ALTER TABLE TEST ADD COLUMN D6 FLOAT(54);
+> exception
+
+SELECT COLUMN_NAME, DATA_TYPE, TYPE_NAME, COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS
+    WHERE TABLE_NAME = 'TEST' ORDER BY ORDINAL_POSITION;
+> COLUMN_NAME DATA_TYPE TYPE_NAME COLUMN_TYPE
+> ----------- --------- --------- ----------------
+> D1          8         DOUBLE    DOUBLE
+> D2          8         DOUBLE    DOUBLE PRECISION
+> D3          8         DOUBLE    FLOAT
+> D4          8         DOUBLE    FLOAT(25)
+> D5          8         DOUBLE    FLOAT(53)
+> rows (ordered): 5
+
+SCRIPT NODATA NOPASSWORDS NOSETTINGS TABLE TEST;
+> SCRIPT
+> --------------------------------------------------------------------------------------------------------
+> -- 0 +/- SELECT COUNT(*) FROM PUBLIC.TEST;
+> CREATE CACHED TABLE PUBLIC.TEST( D1 DOUBLE, D2 DOUBLE PRECISION, D3 FLOAT, D4 FLOAT(25), D5 FLOAT(53) );
+> CREATE USER IF NOT EXISTS SA PASSWORD '' ADMIN;
+> rows: 3
+
+DROP TABLE TEST;
+> ok

h2/src/test/org/h2/test/scripts/datatypes/real.sql

@@ -2,3 +2,30 @@
 -- and the EPL 1.0 (http://h2database.com/html/license.html).
 -- Initial Developer: H2 Group
 --
+
+CREATE TABLE TEST(D1 REAL, D2 FLOAT4, D3 FLOAT(0), D4 FLOAT(24));
+> ok
+
+ALTER TABLE TEST ADD COLUMN D5 FLOAT(-1);
+> exception
+
+SELECT COLUMN_NAME, DATA_TYPE, TYPE_NAME, COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS
+    WHERE TABLE_NAME = 'TEST' ORDER BY ORDINAL_POSITION;
+> COLUMN_NAME DATA_TYPE TYPE_NAME COLUMN_TYPE
+> ----------- --------- --------- -----------
+> D1          7         REAL      REAL
+> D2          7         REAL      FLOAT4
+> D3          7         REAL      FLOAT(0)
+> D4          7         REAL      FLOAT(24)
+> rows (ordered): 4
+
+SCRIPT NODATA NOPASSWORDS NOSETTINGS TABLE TEST;
+> SCRIPT
+> ---------------------------------------------------------------------------------
+> -- 0 +/- SELECT COUNT(*) FROM PUBLIC.TEST;
+> CREATE CACHED TABLE PUBLIC.TEST( D1 REAL, D2 FLOAT4, D3 FLOAT(0), D4 FLOAT(24) );
+> CREATE USER IF NOT EXISTS SA PASSWORD '' ADMIN;
+> rows: 3
+
+DROP TABLE TEST;
+> ok