org.postgresql.jdbc.PgResultSetMetaData Maven / Gradle / Ivy
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/*
* Copyright (c) 2004, PostgreSQL Global Development Group
* See the LICENSE file in the project root for more information.
*/
package org.postgresql.jdbc;
import static org.postgresql.util.internal.Nullness.castNonNull;
import org.postgresql.PGResultSetMetaData;
import org.postgresql.core.BaseConnection;
import org.postgresql.core.Field;
import org.postgresql.core.ServerVersion;
import org.postgresql.util.GT;
import org.postgresql.util.Gettable;
import org.postgresql.util.GettableHashMap;
import org.postgresql.util.JdbcBlackHole;
import org.postgresql.util.PSQLException;
import org.postgresql.util.PSQLState;
import org.checkerframework.checker.nullness.qual.Nullable;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
public class PgResultSetMetaData implements ResultSetMetaData, PGResultSetMetaData {
protected final BaseConnection connection;
protected final Field[] fields;
private boolean fieldInfoFetched;
/**
* Initialise for a result with a tuple set and a field descriptor set
*
* @param connection the connection to retrieve metadata
* @param fields the array of field descriptors
*/
public PgResultSetMetaData(BaseConnection connection, Field[] fields) {
this.connection = connection;
this.fields = fields;
this.fieldInfoFetched = false;
}
@Override
public int getColumnCount() throws SQLException {
return fields.length;
}
/**
* {@inheritDoc}
*
* It is believed that PostgreSQL does not support this feature.
*
* @param column the first column is 1, the second is 2...
* @return true if so
* @exception SQLException if a database access error occurs
*/
@Override
public boolean isAutoIncrement(int column) throws SQLException {
fetchFieldMetaData();
Field field = getField(column);
FieldMetadata metadata = field.getMetadata();
return metadata != null && metadata.autoIncrement;
}
/**
* {@inheritDoc}
*
*
Does a column's case matter? ASSUMPTION: Any field that is not obviously case insensitive is
* assumed to be case sensitive
*
* @param column the first column is 1, the second is 2...
* @return true if so
* @exception SQLException if a database access error occurs
*/
@Override
public boolean isCaseSensitive(int column) throws SQLException {
Field field = getField(column);
return connection.getTypeInfo().isCaseSensitive(field.getOID());
}
/**
* {@inheritDoc}
*
*
Can the column be used in a WHERE clause? Basically for this, I split the functions into two
* types: recognised types (which are always useable), and OTHER types (which may or may not be
* useable). The OTHER types, for now, I will assume they are useable. We should really query the
* catalog to see if they are useable.
*
* @param column the first column is 1, the second is 2...
* @return true if they can be used in a WHERE clause
* @exception SQLException if a database access error occurs
*/
@Override
public boolean isSearchable(int column) throws SQLException {
return true;
}
/**
* {@inheritDoc}
*
*
Is the column a cash value? 6.1 introduced the cash/money type, which haven't been incorporated
* as of 970414, so I just check the type name for both 'cash' and 'money'
*
* @param column the first column is 1, the second is 2...
* @return true if its a cash column
* @exception SQLException if a database access error occurs
*/
@Override
public boolean isCurrency(int column) throws SQLException {
String typeName = getPGType(column);
return "cash".equals(typeName) || "money".equals(typeName);
}
@Override
public int isNullable(int column) throws SQLException {
fetchFieldMetaData();
Field field = getField(column);
FieldMetadata metadata = field.getMetadata();
return metadata == null ? ResultSetMetaData.columnNullable : metadata.nullable;
}
/**
* {@inheritDoc}
*
*
Is the column a signed number? In PostgreSQL, all numbers are signed, so this is trivial.
* However, strings are not signed (duh!)
*
* @param column the first column is 1, the second is 2...
* @return true if so
* @exception SQLException if a database access error occurs
*/
@Override
public boolean isSigned(int column) throws SQLException {
Field field = getField(column);
return connection.getTypeInfo().isSigned(field.getOID());
}
@Override
public int getColumnDisplaySize(int column) throws SQLException {
Field field = getField(column);
return connection.getTypeInfo().getDisplaySize(field.getOID(), field.getMod());
}
@Override
public String getColumnLabel(int column) throws SQLException {
Field field = getField(column);
return field.getColumnLabel();
}
@Override
public String getColumnName(int column) throws SQLException {
return getColumnLabel(column);
}
@Override
public String getBaseColumnName(int column) throws SQLException {
Field field = getField(column);
if (field.getTableOid() == 0) {
return "";
}
fetchFieldMetaData();
FieldMetadata metadata = field.getMetadata();
return metadata == null ? "" : metadata.columnName;
}
@Override
public String getSchemaName(int column) throws SQLException {
return "";
}
private boolean populateFieldsWithMetadata(Gettable metadata) {
boolean allOk = true;
for (Field field : fields) {
if (field.getMetadata() != null) {
// No need to update metadata
continue;
}
final FieldMetadata fieldMetadata =
metadata.get(new FieldMetadata.Key(field.getTableOid(), field.getPositionInTable()));
if (fieldMetadata == null) {
allOk = false;
} else {
field.setMetadata(fieldMetadata);
}
}
fieldInfoFetched |= allOk;
return allOk;
}
private void fetchFieldMetaData() throws SQLException {
if (fieldInfoFetched) {
return;
}
if (populateFieldsWithMetadata(connection.getFieldMetadataCache())) {
return;
}
StringBuilder sql = new StringBuilder(
"SELECT c.oid, a.attnum, a.attname, c.relname, n.nspname, "
+ "a.attnotnull OR (t.typtype = 'd' AND t.typnotnull), ");
if ( connection.haveMinimumServerVersion(ServerVersion.v10)) {
sql.append("a.attidentity != '' OR pg_catalog.pg_get_expr(d.adbin, d.adrelid) LIKE '%nextval(%' ");
} else {
sql.append("pg_catalog.pg_get_expr(d.adbin, d.adrelid) LIKE '%nextval(%' ");
}
sql.append("FROM pg_catalog.pg_class c "
+ "JOIN pg_catalog.pg_namespace n ON (c.relnamespace = n.oid) "
+ "JOIN pg_catalog.pg_attribute a ON (c.oid = a.attrelid) "
+ "JOIN pg_catalog.pg_type t ON (a.atttypid = t.oid) "
+ "LEFT JOIN pg_catalog.pg_attrdef d ON (d.adrelid = a.attrelid AND d.adnum = a.attnum) "
+ "JOIN (");
// 7.4 servers don't support row IN operations (a,b) IN ((c,d),(e,f))
// so we've got to fake that with a JOIN here.
//
boolean hasSourceInfo = false;
for (Field field : fields) {
if (field.getMetadata() != null) {
continue;
}
if (hasSourceInfo) {
sql.append(" UNION ALL ");
}
sql.append("SELECT ");
sql.append(field.getTableOid());
if (!hasSourceInfo) {
sql.append(" AS oid ");
}
sql.append(", ");
sql.append(field.getPositionInTable());
if (!hasSourceInfo) {
sql.append(" AS attnum");
}
if (!hasSourceInfo) {
hasSourceInfo = true;
}
}
sql.append(") vals ON (c.oid = vals.oid AND a.attnum = vals.attnum) ");
if (!hasSourceInfo) {
fieldInfoFetched = true;
return;
}
Statement stmt = connection.createStatement();
ResultSet rs = null;
GettableHashMap md = new GettableHashMap<>();
try {
rs = stmt.executeQuery(sql.toString());
while (rs.next()) {
int table = (int) rs.getLong(1);
int column = (int) rs.getLong(2);
String columnName = castNonNull(rs.getString(3));
String tableName = castNonNull(rs.getString(4));
String schemaName = castNonNull(rs.getString(5));
int nullable =
rs.getBoolean(6) ? ResultSetMetaData.columnNoNulls : ResultSetMetaData.columnNullable;
boolean autoIncrement = rs.getBoolean(7);
FieldMetadata fieldMetadata =
new FieldMetadata(columnName, tableName, schemaName, nullable, autoIncrement);
FieldMetadata.Key key = new FieldMetadata.Key(table, column);
md.put(key, fieldMetadata);
}
} finally {
JdbcBlackHole.close(rs);
JdbcBlackHole.close(stmt);
}
populateFieldsWithMetadata(md);
connection.getFieldMetadataCache().putAll(md);
}
@Override
public String getBaseSchemaName(int column) throws SQLException {
fetchFieldMetaData();
Field field = getField(column);
FieldMetadata metadata = field.getMetadata();
return metadata == null ? "" : metadata.schemaName;
}
@Override
public int getPrecision(int column) throws SQLException {
Field field = getField(column);
return connection.getTypeInfo().getPrecision(field.getOID(), field.getMod());
}
@Override
public int getScale(int column) throws SQLException {
Field field = getField(column);
return connection.getTypeInfo().getScale(field.getOID(), field.getMod());
}
@Override
public String getTableName(int column) throws SQLException {
return getBaseTableName(column);
}
@Override
public String getBaseTableName(int column) throws SQLException {
fetchFieldMetaData();
Field field = getField(column);
FieldMetadata metadata = field.getMetadata();
return metadata == null ? "" : metadata.tableName;
}
/**
* {@inheritDoc}
*
* As with getSchemaName(), we can say that if
* getTableName() returns n/a, then we can too - otherwise, we need to work on it.
*
* @param column the first column is 1, the second is 2...
* @return catalog name, or "" if not applicable
* @exception SQLException if a database access error occurs
*/
@Override
public String getCatalogName(int column) throws SQLException {
return "";
}
@Override
public int getColumnType(int column) throws SQLException {
return getSQLType(column);
}
@Override
public int getFormat(int column) throws SQLException {
return getField(column).getFormat();
}
@Override
public String getColumnTypeName(int column) throws SQLException {
String type = getPGType(column);
if (isAutoIncrement(column)) {
if ("int4".equals(type)) {
return "serial";
} else if ("int8".equals(type)) {
return "bigserial";
} else if ("int2".equals(type) && connection.haveMinimumServerVersion(ServerVersion.v9_2)) {
return "smallserial";
}
}
return castNonNull(type);
}
/**
* {@inheritDoc}
*
*
In reality, we would have to check the GRANT/REVOKE
* stuff for this to be effective, and I haven't really looked into that yet, so this will get
* re-visited.
*
* @param column the first column is 1, the second is 2, etc.*
* @return true if so*
* @exception SQLException if a database access error occurs
*/
@Override
public boolean isReadOnly(int column) throws SQLException {
return false;
}
/**
* {@inheritDoc}
*
*
In reality have to check
* the GRANT/REVOKE stuff, which I haven't worked with as yet. However, if it isn't ReadOnly, then
* it is obviously writable.
*
* @param column the first column is 1, the second is 2, etc.
* @return true if so
* @exception SQLException if a database access error occurs
*/
@Override
public boolean isWritable(int column) throws SQLException {
return !isReadOnly(column);
}
/**
* {@inheritDoc}
*
*
Hmmm...this is a bad one, since the two
* preceding functions have not been really defined. I cannot tell is the short answer. I thus
* return isWritable() just to give us an idea.
*
* @param column the first column is 1, the second is 2, etc..
* @return true if so
* @exception SQLException if a database access error occurs
*/
@Override
public boolean isDefinitelyWritable(int column) throws SQLException {
return false;
}
// ********************************************************
// END OF PUBLIC INTERFACE
// ********************************************************
/**
* For several routines in this package, we need to convert a columnIndex into a Field[]
* descriptor. Rather than do the same code several times, here it is.
*
* @param columnIndex the first column is 1, the second is 2...
* @return the Field description
* @exception SQLException if a database access error occurs
*/
protected Field getField(int columnIndex) throws SQLException {
if (columnIndex < 1 || columnIndex > fields.length) {
throw new PSQLException(
GT.tr("The column index is out of range: {0}, number of columns: {1}.",
columnIndex, fields.length),
PSQLState.INVALID_PARAMETER_VALUE);
}
return fields[columnIndex - 1];
}
protected @Nullable String getPGType(int columnIndex) throws SQLException {
return connection.getTypeInfo().getPGType(getField(columnIndex).getOID());
}
protected int getSQLType(int columnIndex) throws SQLException {
return connection.getTypeInfo().getSQLType(getField(columnIndex).getOID());
}
// ** JDBC 2 Extensions **
// This can hook into our PG_Object mechanism
@Override
public String getColumnClassName(int column) throws SQLException {
Field field = getField(column);
String result = connection.getTypeInfo().getJavaClass(field.getOID());
if (result != null) {
return result;
}
int sqlType = getSQLType(column);
if (sqlType == Types.ARRAY) {
return "java.sql.Array";
} else {
String type = getPGType(column);
if ("unknown".equals(type)) {
return "java.lang.String";
}
return "java.lang.Object";
}
}
@Override
public boolean isWrapperFor(Class iface) throws SQLException {
return iface.isAssignableFrom(getClass());
}
@Override
public T unwrap(Class iface) throws SQLException {
if (iface.isAssignableFrom(getClass())) {
return iface.cast(this);
}
throw new SQLException("Cannot unwrap to " + iface.getName());
}
}