package liquibase.sqlgenerator.core;
import liquibase.change.ColumnConfig;
import liquibase.database.Database;
import liquibase.database.core.*;
import liquibase.exception.UnexpectedLiquibaseException;
import liquibase.exception.ValidationErrors;
import liquibase.sql.Sql;
import liquibase.sql.UnparsedSql;
import liquibase.sqlgenerator.SqlGeneratorChain;
import liquibase.statement.core.SelectFromDatabaseChangeLogStatement;
import liquibase.util.StringUtils;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
public class SelectFromDatabaseChangeLogGenerator extends AbstractSqlGenerator<SelectFromDatabaseChangeLogStatement> {
@Override
public ValidationErrors validate(SelectFromDatabaseChangeLogStatement statement, Database database, SqlGeneratorChain sqlGeneratorChain) {
ValidationErrors errors = new ValidationErrors();
errors.checkRequiredField("columnToSelect", statement.getColumnsToSelect());
return errors;
}
@Override
public Sql[] generateSql(SelectFromDatabaseChangeLogStatement statement, final Database database, SqlGeneratorChain sqlGeneratorChain) {
List<ColumnConfig> columnsToSelect = Arrays.asList(statement.getColumnsToSelect());
String sql = "SELECT " + (database instanceof MSSQLDatabase && statement.getLimit() != null ? "TOP "+statement.getLimit()+" " : "") + StringUtils.join(columnsToSelect, ",", new StringUtils.StringUtilsFormatter<ColumnConfig>() {
@Override
public String toString(ColumnConfig column) {
if (column.getComputed() != null && column.getComputed()) {
return column.getName();
} else {
return database.escapeColumnName(null, null, null, column.getName());
}
}
}).toUpperCase() + " FROM " +
database.escapeTableName(database.getLiquibaseCatalogName(), database.getLiquibaseSchemaName(), database.getDatabaseChangeLogTableName());
SelectFromDatabaseChangeLogStatement.WhereClause whereClause = statement.getWhereClause();
if (whereClause != null) {
if (whereClause instanceof SelectFromDatabaseChangeLogStatement.ByTag) {
sql += " WHERE "+database.escapeColumnName(null, null, null, "TAG")+"='" + ((SelectFromDatabaseChangeLogStatement.ByTag) whereClause).getTagName() + "'";
} else if (whereClause instanceof SelectFromDatabaseChangeLogStatement.ByNotNullCheckSum) {
sql += " WHERE "+database.escapeColumnName(null, null, null, "MD5SUM")+" IS NOT NULL";
} else {
throw new UnexpectedLiquibaseException("Unknown where clause type: " + whereClause.getClass().getName());
}
}
if (statement.getOrderByColumns() != null && statement.getOrderByColumns().length > 0) {
sql += " ORDER BY ";
Iterator<String> orderBy = Arrays.asList(statement.getOrderByColumns()).iterator();
while (orderBy.hasNext()) {
String orderColumn = orderBy.next();
String[] orderColumnData = orderColumn.split(" ");
sql += database.escapeColumnName(null, null, null, orderColumnData[0]);
if (orderColumnData.length == 2) {
sql += " ";
sql += orderColumnData[1].toUpperCase();
}
if (orderBy.hasNext()) {
sql += ", ";
}
}
}
if (statement.getLimit() != null) {
if (database instanceof OracleDatabase) {
if (whereClause == null) {
sql += " WHERE ROWNUM="+statement.getLimit();
} else {
sql += " AND ROWNUM="+statement.getLimit();
}
} else if (database instanceof MySQLDatabase || database instanceof PostgresDatabase) {
sql += " LIMIT "+statement.getLimit();
} else if (database instanceof DB2Database) {
sql += " FETCH FIRST "+statement.getLimit()+" ROWS ONLY";
}
}
return new Sql[]{
new UnparsedSql(sql)
};
}
}